#include <bits/stdc++.h>
#define mrep(i, s, n) for (int i = (s); i < (int)(n); i++)
#define rep(i, n) mrep(i, 0, n)
using namespace std;
using ll = long long;
const int INF = int(1e+9)+1;
const ll INFL = ll(1e+18)+1;

int main() {
    string sa, sb;
    cin >> sa >> sb;

    while(sa.size() < 32) {sa = '0'+sa;}
    while(sb.size() < 32) {sb = '0'+sb;}

    bitset<32> bs1(sa), bs2(sb);
    cout << (bs1^bs2).to_ullong() << endl;
}