import sys
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
INF = 2 ** 63 - 1
mod = 998244353

def solve():
    x = input()
    y = input()

    for i in range(min(len(x), len(y))):
        if x[i] > y[i]:
            print('X')
            return
        elif x[i] < y[i]:
            print('Y')
            return
    if len(x) > len(y):
        z = x[len(y):]
        for i in range(min(len(z), len(y))):
            if y[i] > z[i]:
                print('Y')
                return
            elif y[i] < z[i]:
                print('X')
                return
        print('X')
    elif len(x) <= len(y):
        z = y[len(x):]
        for i in range(min(len(z), len(x))):
            if x[i] > z[i]:
                print('X')
                return
            elif x[i] < z[i]:
                print('Y')
                return
        print('Y')
        
for _ in range(ii()):
    solve()