#include <bits/stdc++.h>
using namespace std;
ifstream f("adunare.in");
ofstream g("adunare.out");

int getSum(int p, int q)
{
    int result = p ^ q; // + without carry 0+0=0, 0+1=1+0=1, 1+1=0
    int carry = (p & q) << 1; // 1+1=2
    if (carry != 0) {
        return getSum(result, carry);
    }
    return result;
}

int main() {

    int a, b;
    f>>a>>b;
    g<<getSum(a,b)<<'\n';

    f.close(); g.close();
    return 0;
}