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