AIME 2019a Problem 4
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A soccer team has available players. A fixed set of players starts the game, while the other are available as substitutes. During the game, the coach may make as many as substitutions, where any one of the players in the game is replaced by one of the substitutes. No player removed from the game may reenter the game, although a substitute entering the game may be replaced later. No two substitutions can happen at the same time. The players involved and the order of the substitutions matter. Let be the number of ways the coach can make substitutions during the game (including the possibility of making no substitutions). Find the remainder when is divided by .
Dataset text AIME 1983 to 2026. Quoted with source.
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