import sys







def main():
    t = int(input())
    Q = sys.stdin.read().split()
    for qi in range(t):
        X = Q[2*qi]
        Y = Q[2*qi+1]
        nx, ny = len(X), len(Y)
        ok = False
        for i in range(max(nx, ny)):
            xi = i if i < nx else i % nx
            yi = i if i < ny else i % ny
            if X[xi] > Y[yi]:
                print('X')
                ok = True
            elif X[xi] < Y[yi]:
                print('Y')
                ok = True
            else:
                continue
            break
        if not ok: print('X' if nx > ny else 'Y')









if __name__ == '__main__':
    main()