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