#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>
#include <bitset>
using namespace std;


int main() {

    unsigned long long A, C;
    cin >> A >> C;
    bitset<40> a(A);
    bitset<40> c(C);

    bitset<40> b = a ^ c;

    cout << b.to_ullong() << endl;


    return 0;
}