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