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