#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a[101], x = 0;
  string s1, s2;
  cin >> s1 >> s2;
  for (int i = 0; i < s1.size(); i++) {
    if (s1[i] != s2[i])
      a[i] = 1;
    else
      a[i] = 0;
    x++;
  }
  for (int i = 0; i < x; i++) {
    cout << a[i];
  }
  return 0;
}
