Taiwan IMO Selection Camp
397 problems here, rated 4.4 to 7.7 on our scale (AIME to National Olympiad, round 2). 396 of them ask for a proof. Years covered: 2018–2023.
| # | Topic | Diff | Type | Year | |
|---|---|---|---|---|---|
| 1 | Combinatorics | 4.4 | proof | — | open |
| 2 | Geometry | 4.4 | proof | — | open |
| 3 | Geometry | 4.4 | proof | — | open |
| 4 | Combinatorics | 4.4 | proof | — | open |
| 5 | Geometry | 4.4 | proof | 2022 | open |
| 6 | Geometry | 4.4 | proof | 2021 | open |
| 7 | Geometry | 4.4 | proof | — | open |
| 8 | Geometry | 4.5 | proof | — | open |
| 9 | Geometry | 4.5 | proof | — | open |
| 10 | Geometry | 4.5 | proof | — | open |
| 11 | Algebra | 4.5 | proof | — | open |
| 12 | Geometry | 4.5 | proof | — | open |
| 13 | Geometry | 4.5 | proof | — | open |
| 14 | Number theory | 4.5 | proof | 2023 | open |
| 15 | Geometry | 4.5 | proof | — | open |
| 16 | Geometry | 4.5 | proof | — | open |
| 17 | Geometry | 4.5 | proof | — | open |
| 18 | Geometry | 4.6 | proof | — | open |
| 19 | Number theory | 4.6 | proof | — | open |
| 20 | Algebra | 4.6 | proof | — | open |
| 21 | Algebra | 4.6 | proof | — | open |
| 22 | Geometry | 4.6 | proof | — | open |
| 23 | Geometry | 4.6 | proof | — | open |
| 24 | Combinatorics | 4.7 | answer | — | open |
| 25 | Combinatorics | 4.7 | proof | — | open |
| 26 | Number theory | 4.7 | proof | — | open |
| 27 | Algebra | 4.7 | proof | — | open |
| 28 | Combinatorics | 4.7 | proof | 2018 | open |
| 29 | Number theory | 4.7 | proof | 2022 | open |
| 30 | Algebra | 4.8 | proof | — | open |
| 31 | Combinatorics | 4.8 | proof | — | open |
| 32 | Combinatorics | 4.8 | proof | — | open |
| 33 | Geometry | 4.8 | proof | — | open |
| 34 | Algebra | 4.9 | proof | — | open |
| 35 | Number theory | 4.9 | proof | — | open |
| 36 | Geometry | 4.9 | proof | — | open |
| 37 | Combinatorics | 4.9 | proof | 2021 | open |
| 38 | Geometry | 4.9 | proof | 2022 | open |
| 39 | Number theory | 4.9 | proof | — | open |
| 40 | Algebra | 4.9 | proof | — | open |
| 41 | Combinatorics | 4.9 | proof | — | open |
| 42 | Combinatorics | 4.9 | proof | 2018 | open |
| 43 | Geometry | 4.9 | proof | — | open |
| 44 | Combinatorics | 4.9 | proof | — | open |
| 45 | Algebra | 4.9 | proof | — | open |
| 46 | Algebra | 4.9 | proof | — | open |
| 47 | Geometry | 4.9 | proof | — | open |
| 48 | Algebra | 5.0 | proof | — | open |
| 49 | Combinatorics | 5.0 | proof | 2023 | open |
| 50 | Geometry | 5.0 | proof | — | open |
| 51 | Combinatorics | 5.0 | proof | 2022 | open |
| 52 | Algebra | 5.0 | proof | — | open |
| 53 | Geometry | 5.0 | proof | — | open |
| 54 | Combinatorics | 5.0 | proof | — | open |
| 55 | Combinatorics | 5.0 | proof | — | open |
| 56 | Number theory | 5.0 | proof | — | open |
| 57 | Combinatorics | 5.1 | proof | — | open |
| 58 | Number theory | 5.1 | proof | 2018 | open |
| 59 | Number theory | 5.1 | proof | — | open |
| 60 | Geometry | 5.1 | proof | — | open |
| 61 | Number theory | 5.1 | proof | — | open |
| 62 | Geometry | 5.1 | proof | — | open |
| 63 | Geometry | 5.1 | proof | — | open |
| 64 | Geometry | 5.1 | proof | — | open |
| 65 | Geometry | 5.1 | proof | — | open |
| 66 | Algebra | 5.1 | proof | — | open |
| 67 | Geometry | 5.1 | proof | 2022 | open |
| 68 | Combinatorics | 5.1 | proof | 2022 | open |
| 69 | Algebra | 5.1 | proof | — | open |
| 70 | Geometry | 5.1 | proof | — | open |
| 71 | Geometry | 5.1 | proof | 2022 | open |
| 72 | Combinatorics | 5.1 | proof | 2023 | open |
| 73 | Number theory | 5.1 | proof | — | open |
| 74 | Geometry | 5.1 | proof | — | open |
| 75 | Geometry | 5.2 | proof | 2018 | open |
| 76 | Geometry | 5.2 | proof | 2021 | open |
| 77 | Geometry | 5.2 | proof | 2022 | open |
| 78 | Geometry | 5.2 | proof | — | open |
| 79 | Geometry | 5.2 | proof | 2022 | open |
| 80 | Algebra | 5.2 | proof | — | open |
| 81 | Number theory | 5.2 | proof | — | open |
| 82 | Algebra | 5.2 | proof | — | open |
| 83 | Algebra | 5.2 | proof | — | open |
| 84 | Algebra | 5.2 | proof | — | open |
| 85 | Combinatorics | 5.2 | proof | 2022 | open |
| 86 | Geometry | 5.2 | proof | — | open |
| 87 | Combinatorics | 5.2 | proof | — | open |
| 88 | Combinatorics | 5.2 | proof | — | open |
| 89 | Geometry | 5.2 | proof | — | open |
| 90 | Algebra | 5.2 | proof | — | open |
| 91 | Geometry | 5.2 | proof | — | open |
| 92 | Geometry | 5.2 | proof | — | open |
| 93 | Algebra | 5.2 | proof | 2021 | open |
| 94 | Geometry | 5.2 | proof | — | open |
| 95 | Algebra | 5.2 | proof | — | open |
| 96 | Geometry | 5.3 | proof | — | open |
| 97 | Geometry | 5.3 | proof | 2023 | open |
| 98 | Combinatorics | 5.3 | proof | — | open |
| 99 | Algebra | 5.3 | proof | — | open |
| 100 | Geometry | 5.3 | proof | — | open |
| 101 | Algebra | 5.3 | proof | — | open |
| 102 | Algebra | 5.3 | proof | 2018 | open |
| 103 | Algebra | 5.3 | proof | 2022 | open |
| 104 | Algebra | 5.3 | proof | — | open |
| 105 | Algebra | 5.3 | proof | — | open |
| 106 | Geometry | 5.3 | proof | 2022 | open |
| 107 | Algebra | 5.3 | proof | — | open |
| 108 | Number theory | 5.4 | proof | — | open |
| 109 | Algebra | 5.4 | proof | — | open |
| 110 | Algebra | 5.4 | proof | — | open |
| 111 | Algebra | 5.4 | proof | — | open |
| 112 | Number theory | 5.4 | proof | — | open |
| 113 | Number theory | 5.4 | proof | — | open |
| 114 | Number theory | 5.4 | proof | — | open |
| 115 | Algebra | 5.4 | proof | — | open |
| 116 | Geometry | 5.4 | proof | — | open |
| 117 | Algebra | 5.4 | proof | — | open |
| 118 | Algebra | 5.4 | proof | — | open |
| 119 | Combinatorics | 5.4 | proof | 2022 | open |
| 120 | Combinatorics | 5.4 | proof | — | open |
| 121 | Algebra | 5.4 | proof | — | open |
| 122 | Geometry | 5.4 | proof | — | open |
| 123 | Number theory | 5.4 | proof | — | open |
| 124 | Number theory | 5.4 | proof | — | open |
| 125 | Geometry | 5.4 | proof | — | open |
| 126 | Geometry | 5.4 | proof | — | open |
| 127 | Geometry | 5.4 | proof | — | open |
| 128 | Algebra | 5.4 | proof | 2023 | open |
| 129 | Algebra | 5.4 | proof | — | open |
| 130 | Combinatorics | 5.4 | proof | — | open |
| 131 | Algebra | 5.5 | proof | — | open |
| 132 | Geometry | 5.5 | proof | — | open |
| 133 | Geometry | 5.5 | proof | — | open |
| 134 | Algebra | 5.5 | proof | — | open |
| 135 | Number theory | 5.5 | proof | — | open |
| 136 | Combinatorics | 5.5 | proof | — | open |
| 137 | Combinatorics | 5.5 | proof | — | open |
| 138 | Algebra | 5.5 | proof | — | open |
| 139 | Geometry | 5.5 | proof | — | open |
| 140 | Algebra | 5.5 | proof | — | open |
| 141 | Algebra | 5.5 | proof | — | open |
| 142 | Combinatorics | 5.5 | proof | — | open |
| 143 | Algebra | 5.5 | proof | — | open |
| 144 | Algebra | 5.5 | proof | — | open |
| 145 | Algebra | 5.5 | proof | — | open |
| 146 | Algebra | 5.5 | proof | — | open |
| 147 | Algebra | 5.5 | proof | — | open |
| 148 | Geometry | 5.6 | proof | — | open |
| 149 | Geometry | 5.6 | proof | — | open |
| 150 | Algebra | 5.6 | proof | — | open |
| 151 | Geometry | 5.6 | proof | — | open |
| 152 | Geometry | 5.6 | proof | 2022 | open |
| 153 | Number theory | 5.6 | proof | — | open |
| 154 | Geometry | 5.6 | proof | — | open |
| 155 | Algebra | 5.6 | proof | — | open |
| 156 | Number theory | 5.6 | proof | — | open |
| 157 | Algebra | 5.6 | proof | 2023 | open |
| 158 | Algebra | 5.6 | proof | — | open |
| 159 | Algebra | 5.6 | proof | — | open |
| 160 | Number theory | 5.6 | proof | — | open |
| 161 | Algebra | 5.6 | proof | — | open |
| 162 | Number theory | 5.6 | proof | — | open |
| 163 | Combinatorics | 5.6 | proof | 2022 | open |
| 164 | Number theory | 5.6 | proof | — | open |
| 165 | Combinatorics | 5.6 | proof | — | open |
| 166 | Number theory | 5.6 | proof | — | open |
| 167 | Number theory | 5.6 | proof | 2022 | open |
| 168 | Geometry | 5.6 | proof | — | open |
| 169 | Number theory | 5.6 | proof | 2021 | open |
| 170 | Combinatorics | 5.6 | proof | — | open |
| 171 | Algebra | 5.6 | proof | — | open |
| 172 | Geometry | 5.7 | proof | 2023 | open |
| 173 | Combinatorics | 5.7 | proof | — | open |
| 174 | Geometry | 5.7 | proof | 2022 | open |
| 175 | Combinatorics | 5.7 | proof | — | open |
| 176 | Combinatorics | 5.7 | proof | 2022 | open |
| 177 | Combinatorics | 5.7 | proof | — | open |
| 178 | Combinatorics | 5.7 | proof | — | open |
| 179 | Algebra | 5.7 | proof | 2023 | open |
| 180 | Combinatorics | 5.7 | proof | — | open |
| 181 | Number theory | 5.7 | proof | — | open |
| 182 | Geometry | 5.7 | proof | — | open |
| 183 | Algebra | 5.7 | proof | — | open |
| 184 | Number theory | 5.7 | proof | 2021 | open |
| 185 | Combinatorics | 5.8 | proof | — | open |
| 186 | Geometry | 5.8 | proof | 2022 | open |
| 187 | Combinatorics | 5.8 | proof | 2021 | open |
| 188 | Geometry | 5.8 | proof | — | open |
| 189 | Geometry | 5.8 | proof | — | open |
| 190 | Combinatorics | 5.8 | proof | — | open |
| 191 | Number theory | 5.8 | proof | — | open |
| 192 | Geometry | 5.8 | proof | 2022 | open |
| 193 | Algebra | 5.8 | proof | 2021 | open |
| 194 | Algebra | 5.8 | proof | — | open |
| 195 | Algebra | 5.8 | proof | 2023 | open |
| 196 | Algebra | 5.8 | proof | — | open |
| 197 | Algebra | 5.8 | proof | — | open |
| 198 | Algebra | 5.8 | proof | — | open |
| 199 | Geometry | 5.8 | proof | — | open |
| 200 | Number theory | 5.8 | proof | — | open |
| 201 | Algebra | 5.9 | proof | — | open |
| 202 | Combinatorics | 5.9 | proof | — | open |
| 203 | Number theory | 5.9 | proof | 2023 | open |
| 204 | Geometry | 5.9 | proof | — | open |
| 205 | Geometry | 5.9 | proof | 2022 | open |
| 206 | Geometry | 5.9 | proof | — | open |
| 207 | Algebra | 5.9 | proof | — | open |
| 208 | Number theory | 5.9 | proof | — | open |
| 209 | Algebra | 5.9 | proof | — | open |
| 210 | Number theory | 5.9 | proof | — | open |
| 211 | Number theory | 5.9 | proof | 2022 | open |
| 212 | Combinatorics | 5.9 | proof | 2022 | open |
| 213 | Combinatorics | 6.0 | proof | — | open |
| 214 | Combinatorics | 6.0 | proof | — | open |
| 215 | Number theory | 6.0 | proof | — | open |
| 216 | Algebra | 6.0 | proof | 2023 | open |
| 217 | Algebra | 6.0 | proof | — | open |
| 218 | Algebra | 6.0 | proof | — | open |
| 219 | Combinatorics | 6.0 | proof | — | open |
| 220 | Number theory | 6.0 | proof | 2022 | open |
| 221 | Algebra | 6.0 | proof | 2022 | open |
| 222 | Algebra | 6.0 | proof | 2021 | open |
| 223 | Geometry | 6.0 | proof | — | open |
| 224 | Combinatorics | 6.0 | proof | — | open |
| 225 | Number theory | 6.0 | proof | 2021 | open |
| 226 | Number theory | 6.0 | proof | 2023 | open |
| 227 | Geometry | 6.0 | proof | — | open |
| 228 | Algebra | 6.0 | proof | — | open |
| 229 | Number theory | 6.1 | proof | — | open |
| 230 | Algebra | 6.1 | proof | — | open |
| 231 | Combinatorics | 6.1 | proof | 2021 | open |
| 232 | Algebra | 6.1 | proof | 2022 | open |
| 233 | Algebra | 6.1 | proof | — | open |
| 234 | Geometry | 6.1 | proof | — | open |
| 235 | Algebra | 6.1 | proof | — | open |
| 236 | Combinatorics | 6.1 | proof | 2023 | open |
| 237 | Geometry | 6.1 | proof | 2021 | open |
| 238 | Algebra | 6.1 | proof | — | open |
| 239 | Geometry | 6.1 | proof | — | open |
| 240 | Algebra | 6.1 | proof | — | open |
| 241 | Combinatorics | 6.2 | proof | 2021 | open |
| 242 | Geometry | 6.2 | proof | — | open |
| 243 | Geometry | 6.2 | proof | — | open |
| 244 | Geometry | 6.2 | proof | — | open |
| 245 | Combinatorics | 6.2 | proof | 2023 | open |
| 246 | Geometry | 6.2 | proof | 2023 | open |
| 247 | Combinatorics | 6.2 | proof | — | open |
| 248 | Geometry | 6.2 | proof | — | open |
| 249 | Geometry | 6.2 | proof | 2022 | open |
| 250 | Algebra | 6.2 | proof | 2023 | open |
| 251 | Geometry | 6.2 | proof | — | open |
| 252 | Combinatorics | 6.2 | proof | 2021 | open |
| 253 | Geometry | 6.2 | proof | 2018 | open |
| 254 | Number theory | 6.2 | proof | 2023 | open |
| 255 | Algebra | 6.2 | proof | 2023 | open |
| 256 | Geometry | 6.2 | proof | — | open |
| 257 | Combinatorics | 6.2 | proof | 2022 | open |
| 258 | Algebra | 6.2 | proof | — | open |
| 259 | Geometry | 6.2 | proof | — | open |
| 260 | Number theory | 6.3 | proof | 2018 | open |
| 261 | Geometry | 6.3 | proof | — | open |
| 262 | Geometry | 6.3 | proof | — | open |
| 263 | Algebra | 6.3 | proof | — | open |
| 264 | Combinatorics | 6.3 | proof | — | open |
| 265 | Number theory | 6.3 | proof | — | open |
| 266 | Geometry | 6.3 | proof | — | open |
| 267 | Algebra | 6.3 | proof | 2023 | open |
| 268 | Geometry | 6.3 | proof | 2023 | open |
| 269 | Algebra | 6.3 | proof | — | open |
| 270 | Algebra | 6.3 | proof | — | open |
| 271 | Combinatorics | 6.3 | proof | 2021 | open |
| 272 | Combinatorics | 6.4 | proof | — | open |
| 273 | Combinatorics | 6.4 | proof | 2023 | open |
| 274 | Geometry | 6.4 | proof | 2021 | open |
| 275 | Geometry | 6.4 | proof | 2022 | open |
| 276 | Geometry | 6.4 | proof | 2021 | open |
| 277 | Algebra | 6.4 | proof | 2022 | open |
| 278 | Algebra | 6.4 | proof | — | open |
| 279 | Geometry | 6.4 | proof | 2021 | open |
| 280 | Combinatorics | 6.4 | proof | — | open |
| 281 | Geometry | 6.5 | proof | — | open |
| 282 | Combinatorics | 6.5 | proof | — | open |
| 283 | Number theory | 6.5 | proof | 2021 | open |
| 284 | Algebra | 6.5 | proof | — | open |
| 285 | Geometry | 6.5 | proof | — | open |
| 286 | Number theory | 6.5 | proof | 2021 | open |
| 287 | Geometry | 6.5 | proof | 2023 | open |
| 288 | Geometry | 6.5 | proof | 2023 | open |
| 289 | Geometry | 6.5 | proof | 2023 | open |
| 290 | Algebra | 6.5 | proof | 2021 | open |
| 291 | Geometry | 6.5 | proof | 2021 | open |
| 292 | Geometry | 6.5 | proof | 2021 | open |
| 293 | Algebra | 6.5 | proof | — | open |
| 294 | Combinatorics | 6.5 | proof | 2023 | open |
| 295 | Geometry | 6.5 | proof | — | open |
| 296 | Geometry | 6.5 | proof | — | open |
| 297 | Combinatorics | 6.5 | proof | 2023 | open |
| 298 | Number theory | 6.6 | proof | — | open |
| 299 | Geometry | 6.6 | proof | — | open |
| 300 | Geometry | 6.6 | proof | — | open |
| 301 | Algebra | 6.6 | proof | — | open |
| 302 | Algebra | 6.6 | proof | 2022 | open |
| 303 | Number theory | 6.6 | proof | — | open |
| 304 | Geometry | 6.6 | proof | — | open |
| 305 | Combinatorics | 6.6 | proof | 2023 | open |
| 306 | Algebra | 6.6 | proof | — | open |
| 307 | Algebra | 6.6 | proof | 2023 | open |
| 308 | Combinatorics | 6.7 | proof | — | open |
| 309 | Number theory | 6.7 | proof | — | open |
| 310 | Combinatorics | 6.7 | proof | 2023 | open |
| 311 | Combinatorics | 6.7 | proof | 2021 | open |
| 312 | Combinatorics | 6.7 | proof | 2021 | open |
| 313 | Algebra | 6.7 | proof | — | open |
| 314 | Number theory | 6.7 | proof | — | open |
| 315 | Geometry | 6.7 | proof | — | open |
| 316 | Geometry | 6.7 | proof | 2021 | open |
| 317 | Combinatorics | 6.7 | proof | — | open |
| 318 | Number theory | 6.7 | proof | — | open |
| 319 | Algebra | 6.7 | proof | 2022 | open |
| 320 | Number theory | 6.7 | proof | — | open |
| 321 | Geometry | 6.7 | proof | — | open |
| 322 | Geometry | 6.7 | proof | 2023 | open |
| 323 | Combinatorics | 6.7 | proof | — | open |
| 324 | Combinatorics | 6.7 | proof | — | open |
| 325 | Combinatorics | 6.8 | proof | — | open |
| 326 | Geometry | 6.8 | proof | 2021 | open |
| 327 | Algebra | 6.8 | proof | — | open |
| 328 | Algebra | 6.8 | proof | — | open |
| 329 | Number theory | 6.8 | proof | 2022 | open |
| 330 | Geometry | 6.8 | proof | — | open |
| 331 | Algebra | 6.8 | proof | 2021 | open |
| 332 | Number theory | 6.8 | proof | — | open |
| 333 | Geometry | 6.8 | proof | 2021 | open |
| 334 | Algebra | 6.8 | proof | — | open |
| 335 | Combinatorics | 6.8 | proof | — | open |
| 336 | Algebra | 6.8 | proof | 2023 | open |
| 337 | Combinatorics | 6.8 | proof | 2023 | open |
| 338 | Algebra | 6.8 | proof | — | open |
| 339 | Number theory | 6.9 | proof | 2023 | open |
| 340 | Geometry | 6.9 | proof | 2021 | open |
| 341 | Combinatorics | 6.9 | proof | 2021 | open |
| 342 | Geometry | 6.9 | proof | — | open |
| 343 | Geometry | 6.9 | proof | — | open |
| 344 | Geometry | 6.9 | proof | — | open |
| 345 | Number theory | 6.9 | proof | 2022 | open |
| 346 | Combinatorics | 6.9 | proof | 2023 | open |
| 347 | Number theory | 6.9 | proof | 2022 | open |
| 348 | Combinatorics | 6.9 | proof | — | open |
| 349 | Geometry | 6.9 | proof | — | open |
| 350 | Geometry | 6.9 | proof | — | open |
| 351 | Algebra | 6.9 | proof | 2021 | open |
| 352 | Combinatorics | 7.0 | proof | 2022 | open |
| 353 | Number theory | 7.0 | proof | 2022 | open |
| 354 | Algebra | 7.0 | proof | — | open |
| 355 | Algebra | 7.0 | proof | — | open |
| 356 | Combinatorics | 7.0 | proof | — | open |
| 357 | Combinatorics | 7.0 | proof | — | open |
| 358 | Number theory | 7.0 | proof | — | open |
| 359 | Combinatorics | 7.0 | proof | — | open |
| 360 | Algebra | 7.0 | proof | — | open |
| 361 | Algebra | 7.0 | proof | — | open |
| 362 | Algebra | 7.0 | proof | 2023 | open |
| 363 | Combinatorics | 7.0 | proof | — | open |
| 364 | Algebra | 7.0 | proof | — | open |
| 365 | Number theory | 7.1 | proof | 2021 | open |
| 366 | Algebra | 7.1 | proof | — | open |
| 367 | Number theory | 7.1 | proof | 2021 | open |
| 368 | Geometry | 7.1 | proof | 2021 | open |
| 369 | Algebra | 7.1 | proof | — | open |
| 370 | Number theory | 7.1 | proof | 2022 | open |
| 371 | Combinatorics | 7.1 | proof | — | open |
| 372 | Number theory | 7.2 | proof | — | open |
| 373 | Geometry | 7.2 | proof | 2021 | open |
| 374 | Geometry | 7.2 | proof | 2023 | open |
| 375 | Combinatorics | 7.2 | proof | — | open |
| 376 | Geometry | 7.2 | proof | 2021 | open |
| 377 | Algebra | 7.2 | proof | 2018 | open |
| 378 | Combinatorics | 7.3 | proof | — | open |
| 379 | Algebra | 7.3 | proof | 2023 | open |
| 380 | Geometry | 7.3 | proof | 2018 | open |
| 381 | Algebra | 7.3 | proof | — | open |
| 382 | Algebra | 7.3 | proof | 2022 | open |
| 383 | Geometry | 7.3 | proof | 2023 | open |
| 384 | Combinatorics | 7.3 | proof | — | open |
| 385 | Algebra | 7.3 | proof | — | open |
| 386 | Algebra | 7.3 | proof | 2021 | open |
| 387 | Number theory | 7.4 | proof | 2021 | open |
| 388 | Geometry | 7.4 | proof | 2018 | open |
| 389 | Geometry | 7.4 | proof | 2023 | open |
| 390 | Geometry | 7.4 | proof | — | open |
| 391 | Geometry | 7.4 | proof | 2021 | open |
| 392 | Combinatorics | 7.5 | proof | — | open |
| 393 | Algebra | 7.5 | proof | 2023 | open |
| 394 | Combinatorics | 7.5 | proof | — | open |
| 395 | Algebra | 7.6 | proof | — | open |
| 396 | Algebra | 7.6 | proof | 2018 | open |
| 397 | Combinatorics | 7.7 | proof | 2018 | open |
These are sorted by difficulty within the competition, but they aren't a course.
The track is the route through, drawn from all the sources at once.