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