/* -*- coding: utf-8 -*-
 *
 * 3240.cc:  No.3240 Count 8 Included Numbers (Easy) - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* main */

int main() {
  int n;
  scanf("%d", &n);

  int cnt = 0;
  for (int i = 1; i <= n; i++) {
    bool ok = false;
    for (int j = i; j > 0; j /= 10)
      if (j % 10 == 8) { ok = true; break; }
    if (ok) cnt++;
  }

  printf("%d\n", cnt);
  
  return 0;
}