#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  string s1;
  cin >> s >> s1;
  string a = s;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] != s1[i]) {
      a[i] = '1';
    } else {
      a[i] = '0';
    }
  }
  cout << a;
  return 0;
}
