#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  string str1, str2;
  cin >> str1;
  cin >> str2;
  for (int i = 0; i < str1.length(); i++) {
    if (str1[i] != str2[i])
      cout << 1;
    else
      cout << 0;
  }
}
