#include <bits/stdc++.h>
#pragma GCC optimize "trapv"
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  clock_t clk = clock();
  int t = 1;
  while (t--) {
    string s, t;
    cin >> s >> t;
    long long n = (int)s.size();
    string ans = "";
    for (int i = 0; i < n; i++) {
      if (s[i] == t[i])
        ans += '0';
      else
        ans += '1';
    }
    cout << ans << endl;
  }
  cerr << '\n'
       << "Time (in s): " << double(clock() - clk) * 1.0 / CLOCKS_PER_SEC
       << '\n';
}
