#include <bits/stdc++.h>
using namespace std;
char a[101], b[101];
int main(void) {
  char enter;
  char res[101];
  while (scanf("%s%c%s%c", a, &enter, b, &enter) != EOF) {
    int len = strlen(a);
    for (int i = 0; i < len; i++) res[i] = (a[i] == b[i]) ? '0' : '1';
    res[len] = a[len];
    printf("%s\n", res);
  }
  return 0;
}
