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Number theory Difficulty 4.0 AIME Find the answer United Kingdom

Ada the ant starts at a point $O$ on a plane. At the start of each minute she chooses North, South, East or West, and marches $1$ metre in that direction. At the end of $2018$ minutes she finds herself back at $O$ . Let $n$ be the number of possible journeys which she could have made. What is the highest power of $10$ which divides $n$ ?

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