#include <bits/stdc++.h>
using namespace std;
char a[105], b[105];
int read() {
  int k = 0, flag = 1;
  char b = getchar();
  while (b < '0' || b > '9') {
    if (b == '-') flag = -1;
    b = getchar();
  }
  while (b >= '0' && b <= '9') {
    k = (k << 3) + (k << 1) + b - '0';
    b = getchar();
  }
  return k * flag;
}
int main() {
  gets(a), gets(b);
  int len = strlen(a);
  for (int i = 0; i < len; i++) {
    if (a[i] == b[i])
      printf("0");
    else
      printf("1");
  }
  return 0;
}
