#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for (int i = a; i < b; i++)
using ll = long long;

int main(){
	int n;
	cin >> n;
	int ans = 0;
	rep(i, 1, n + 1) {
		string s = to_string(i);
		int sz = s.size();
		int f = 0;
		rep(j, 0, sz) if(s[j] == '8') f++;
		if(f) ans++;
	}
	cout << ans << endl;
}