#include <iostream>
using namespace std;

int getSum(int a, int b) {
    while (b != 0) {
        int temp = a;
        a ^= b;
        b = (temp & b) << 1;
    }
    return a;
}

signed main() {
    int A, B;
    cin >> A >> B;
    cout << getSum(A, B) << endl;
}