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