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