#include <bits/stdc++.h>
using namespace std;
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(NULL);
  string s1;
  string s2;
  cin >> s1;
  cin >> s2;
  int l = s1.length();
  bool s[l];
  memset(s, 0, sizeof(s));
  for (int i = 0; i < s1.size(); i++) {
    if (s1[i] != s2[i]) s[i] = 1;
  }
  for (int i = 0; i < l; i++) {
    cout << s[i];
  }
  return 0;
}
