4. If a number, from the highest digit to the lowest digit, does not decrease at each digit, it is called a "positive number" (such as $12$, $22$, $566$, $1448$, $123456789$, etc.); if a number, from the highest digit to the lowest digit, does not increase at each digit, it is called a "negative number" (such as $21$, $22$, $665$, $8441$, etc.). A number that is neither a positive number nor a negative number is called a "swinging number" (such as $253$, $3473$, $5887$, etc.). Then among the three-digit numbers, there are $\qquad$ swinging numbers.