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