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

#include <atcoder/all>
using namespace atcoder;

using ll = long long;
using mint = modint998244353;

int main() {
    int N;
    cin >> N;
    int ans = 0;
    for(int x = 1; x <= N; x++) {
        int y = x;
        while(y) {
            if(y % 10 == 8) break;
            y /= 10;
        }
        ans += (y > 0);
    }
    cout << ans << endl;
}