After played many kinds of nim games, Xay and Amr decided to play something different. As the judge, I wrote several valid pairs of numbers on the blackboard. For every pair (x, y), it is valid only if -y ≤ x ≤ y and the greatest common divisor of x and y is 1. The typical legal move is to alter just one of these pairs. If we change (x, y) to (a, b):
1. (a, b) should be a valid pair.
2. 1 ≤ b < y if y != 1
3. 1 ≤ b ≤ y, -b < a < b if y = 1.
Furthermore, such a replacement will be legal for Xay only if a*y - b*x < 0, legal for Amr only if a*y - b*x > 0.For example, Xay can change (2, 5) to (1,3), (1,4), (-1,2), (0,1), (-1,1), etc. And Amr can similarly change (2, 5) to (1, 2), (2, 3), (3, 4), (1, 1), etc.
They will play on these pairs alternately. The last one who be able to move is the winner .We have already knew that both Amr and Xay are very clever and they will play this game perfectly. Now, my dear programmers, can you predict that who will be the winner?