X,K = map(int,input().split()) Z = "0"*50+bin(X)[2:] k = 1 L = [] for i in Z[::-1]: if i == "0": L.append(k) k*=2 K = bin(K)[2:] ans = 0 for idx,i in enumerate(K[::-1]): if i == "1": ans += L[idx] print(ans)