#include<algorithm>
#include<iostream>
#include<vector>
#include<map>
#include<cassert>
#include<set>
#include<queue>
using namespace std;
using ll = long long;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int a,b;
    cin>>a>>b;
    int ans = (a|b) - (a&b);
    cout<<ans<<endl;
}