T = int(input())
ans = ["X", "Y"]
for _ in range(T):
    X = list(input())
    Y = list(input())
    if X + Y < Y + X:
        print("Y")
    elif X + Y > Y + X:
        print("X")
    else:
        if len(X) < len(Y):
            print("Y")
        else:
            print("X")