#include <bits/stdc++.h>
using namespace std;
int main() {
  string st1;
  string st2;
  cin >> st1 >> st2;
  for (int i = 0; i < st1.size(); i++) {
    if (st1[i] == st2[i]) {
      cout << "0";
    } else {
      cout << "1";
    }
  }
  return 0;
}
