Two people in a game, player scores by claiming nodes in binary tree. The player who eventually owns more nodes wins the game. Player A and B each claims a node at first. After the first round, a player will only be able to claim a node adjacent to any node owned by himself. A tree node is adjacent to its parent, left right and right child. A node owned cannot be re-claimed. End game when all nodes are owned. If player A gets the first claim at node N, find whether it is possible for player B to win. If yes, find out which node player B should claim at his first move.