x, y = map(int, input().split()) x, y = bin(x)[2:][::-1], bin(y)[2:][::-1] ans = "" for i in range(max(len(x), len(y))): ans += y[i] if i < len(y) else "0" ans += x[i] if i < len(x) else "0" print(int(ans[::-1], 2))