mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

    for _ in range(int(input())):
        S = input().rstrip('\n')
        T = input().rstrip('\n')

        ST = "".join([S, T])
        TS = "".join([T, S])
        if ST > TS:
            print("X")
        elif ST < TS:
            print("Y")
        else:
            if len(S) > len(T):
                print("X")
            else:
                print("Y")


if __name__ == '__main__':
    main()