#include <bits/stdc++.h>
using namespace std;
char s1[105], s2[105];
int main() {
  while (~scanf("%s%s", s1, s2)) {
    for (int i = 0; s1[i]; ++i) {
      s1[i] = (s1[i] != s2[i]) + '0';
    }
    printf("%s\n", s1);
  }
  return 0;
}
