for _ in range(int(input())):
    x = input(); y = input()
    m = len(x); n = len(y)
    for i in range(max(m, n)):
        if x[i%m] > y[i%n]: print("X"); break
        if x[i%m] < y[i%n]: print("Y"); break
    else: print("X" if m > n else "Y")