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