def solve():
    X = input()
    Y = input()

    lX = len(X)
    lY = len(Y)
    l = max(len(X),len(Y))*2

    for i in range(l):
        x,y = X[i%lX],Y[i%lY]
        if x > y:
            return "X"
        elif x < y:
            return "Y"
    
    if lX < lY:
        return "Y"
    else:
        return "X"


t = int(input())
for _ in range(t):
    print(solve())