#include <bits/stdc++.h>
using namespace std;
string a, b, ans;
int n;
int main() {
  cin >> a >> b;
  n = a.size();
  ans.resize(n);
  for (int i = 0; i < n; i++) ans[i] = (a[i] != b[i]) + '0';
  cout << ans << endl;
  return 0;
}
