t = int(input())
for _ in range(t):
    x = list(input())
    y = list(input())
    if len(x) >= len(y):
        for i in range(len(y), len(x)):
            y.append(y[i % len(y)])
        if x >= y:
            print('X')
        else:
            print('Y')
    else:
        for i in range(len(x), len(y)):
            x.append(x[i % len(x)])
        if x > y:
            print('X')
        else:
            print('Y')