#include <bits/stdc++.h>
using namespace std;
int main() {
  char s1[105], s2[105];
  cin.getline(s1, 105);
  cin.getline(s2, 105);
  int i = 0;
  while (s1[i] != '\0') {
    if (s1[i] == s2[i]) {
      cout << 0;
    } else {
      cout << 1;
    }
    i++;
  }
  return 0;
}
