#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  string s;
  cin >> s;
  string t;
  cin >> t;
  int a, b;
  for (int i = 0; i < s.length(); i++) {
    (s[i] == '0') ? a = 0 : a = 1;
    (t[i] == '0') ? b = 0 : b = 1;
    cout << (a ^ b);
  }
  return 0;
}
