#include <bits/stdc++.h>
using namespace std;
void solve() {
  string a, b;
  cin >> a >> b;
  for (long long i = 0; i < a.length(); i++) {
    if (a[i] != b[i])
      a[i] = '1';
    else
      a[i] = '0';
  }
  cout << a << endl;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  solve();
  return 0;
}
