#include <bits/stdc++.h>
using namespace std;
int main() {
  string s1, s2;
  cin >> s1 >> s2;
  for (int i = 0; i < s1.length(); i++) {
    if (s1[i] != s2[i])
      cout << "1";
    else
      cout << "0";
  }
  cout << '\n';
  return 0;
}
