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