from math import gcd

for _ in range(int(input())):
    S = list(input().rstrip())
    T = list(input().rstrip())
    n, m = len(S), len(T)
    ST = S + T
    TS = T + S
    if ST > TS:
        print('X')
    elif ST < TS:
        print('Y')
    else:
        if n > m:
            print('X')
        else:
            print('Y')