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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    int answer = 0;
    for(int i=1; i<=N; i++){
        string s = to_string(i);
        bool ok = false;
        for(auto c : s) ok |= c=='8';
        answer += ok;
    }
    cout << answer << endl;
}