#include <bits/stdc++.h>
using namespace std;
int main() {
  string s1, s2, ans;
  cin >> s1 >> s2;
  for (string::const_iterator i = s1.begin(), j = s2.begin(); i < s1.end();
       i++, j++) {
    if (*i != *j)
      ans += '1';
    else
      ans += '0';
  }
  cout << ans;
  return 0;
}
