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