#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  string s, d, ans = "";
  cin >> s >> d;
  ans.resize(s.size());
  for (int i = 0; i < s.size(); i++)
    (s[i] != d[i] ? ans[i] = '1' : ans[i] = '0');
  cout << ans;
}
