#include <bits/stdc++.h>
using namespace std;
char res(char n1, char n2) {
  char r = '0';
  if (n1 != n2) {
    r = '1';
  }
  return r;
}
int main() {
  string n1, n2;
  cin >> n1 >> n2;
  for (int i = 0; i < n1.size(); ++i) {
    cout << res(n1[i], n2[i]);
  }
  return 0;
}
