#include <bits/stdc++.h>
using namespace std;
int main() {
  string a, b, ans = "";
  cin >> a >> b;
  int x = a.length();
  for (int i = 0; i < x; i++) {
    if (a[i] == b[i]) {
      ans += "0";
    } else {
      ans += "1";
    }
  }
  cout << ans;
}
