#include <bits/stdc++.h>
int main() {
  char s1[102], s2[102];
  scanf("%s %s", s1, s2);
  for (int i = 0; i < strlen(s1); i++) {
    if (s1[i] != s2[i])
      s1[i] = '1';
    else
      s1[i] = '0';
  }
  printf("%s\n", s1);
  return 0;
}
