#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  string s1, s2, final;
  cin >> s1 >> s2;
  for (int i = 0; i < s1.length(); i++) {
    if (s1[i] != s2[i]) {
      final += '1';
    } else {
      final += '0';
    }
  }
  cout << final;
  return 0;
}
