There are two piles of cards, one with $n$ cards and the other with $m$ cards. $A$ and $B$ play alternately, performing one of the following actions in each turn. following operations: a) Remove a card from a pile. b) Remove one card from each pile. c) Move a card from one pile to the other. Player $A$ always starts the game and whoever takes the last one letter wins . Determine if there is a winning strategy based on $m$ and $n$, so that one of the players following her can win always.