#include <bits/stdc++.h>
using namespace std;

int main() {
    int m, n;
    cin >> n >> m;

    bitset<30> bm(m);
    bitset<30> bn(n);
    bitset<30> ans;
    for(int i = 0; i<30;i++){
        if(i%2 == 0) ans[i] = bm[i];
        if(i%2!= 0){
            if(bn[i] == 1) ans[i] = 0;
            else ans[i] = bm[i];
        }
    }
    cout << ans.to_ulong();
}