#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vl = vector<long>;
using vll = vector<long long>;
using vs = vector<string>;
using vc = vector<char>;
using pll = pair<long long, long long>;
const int INF = 1e9;
using Graph = vector<vector<int>>;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

ll baseN_to_base10(string n, ll b){
    reverse(n.begin(), n.end());
    long long res = 0;
    ll m = n.size();
    ll count = 1;
    for(int i = 0; i < m; i++){
        res += (n[i] - '0')*count;
        count *= b;
    }
    return res;
}

int main() {
  string a,b;
  cin >> a >> b;
  bitset<30> x(a),y(b);
  string f;
  rep(i,30){
    if(x.test(i) && y.test(i))f = '0' + f;
    else if(!x.test(i) && y.test(i))f = '1' + f;
    else if(x.test(i) && !y.test(i))f = '1' + f;
    else if(!x.test(i) && !y.test(i))f = '0' + f;
  }
  cout << baseN_to_base10(f,2) << endl;
}