Given a set of nonnegative integers a1, a2, ... an, Alice and Bob play a game with three rules
1) Alice goes first, and Bob goes next (they alternate turns)
2) A single turn consists of choosing some positive integer ai from the sequence, and replacing it with ai — d, where d is some divisor of ai.
3) When a player has no valid moves remaining, they lose.
Let's suppose (a1, a2, a3) = (1, 5, 4). Then on the first move Alice can make the list (1, 5, 2) by subtracting 2 from the third number (since 2 divides 4). Then Bob can get (1, 0, 2) by subtracting 5 from the middle number (5 divides 5), etc.