#include <bits/stdc++.h>
const double eps = 1e-8;
const int oo = 0x3f3f3f3f;
using namespace std;
string a, b;
bool read() {
  if (!(cin >> a)) return false;
  cin >> b;
  return true;
}
void process() {
  vector<int> v;
  for (int i = 0; i < a.length(); i++) {
    if (a[i] != b[i]) {
      v.push_back(1);
    } else {
      v.push_back(0);
    }
  }
  for (int i = 0; i < a.length(); i++) {
    cout << v[i];
  }
  cout << endl;
}
int main() {
  int t = -1;
  while (t-- && read()) {
    process();
  }
  return 0;
}
