Subtraction Game

 

Start with a number; letís say 17. Two players take turns to do subtractions. Each turn a player can subtract 1, 2 or 3 from the number; the result is then handed to the other player for the next turn; and so on. The player who reaches zero wins. (That is, the player who has no move loses.)

 

What is the strategy to win ?

 

 

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