#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n;
  cin >> n;
  int ans = 0;
  for (int i = 1; i <= n; ++i) {
    string s = to_string(i);
    if (s.contains('8')) ans++;
  }
  cout << ans << '\n';
  return 0;
}