#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  string s1, s2;
  cin >> s1 >> s2;
  string s3;
  for (int i = 0; i < s1.length(); i++) {
    if (s1[i] != s2[i]) {
      s3 += '1';
    } else {
      s3 += '0';
    }
  }
  cout << s3;
  return 0;
}
