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