A and B play the divisor erasing game. The natural numbers from 1 to N are written on a blackboard, one of each.
On your turn you pick one number that is still on the board and erase it, and you also erase every divisor of that number that is still on the board. For example, if 2, 3, 4, 5, 6 remain and you pick 6, then 6 is erased together with its divisors 2 and 3. You cannot pass your turn without erasing anything. The player who erases the last number loses.
A moves first and both players play optimally. Find the player who wins.