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