#include <iostream>
#include <string>
using namespace std;

bool is_include_8(string &s) {
    bool ret = false;
    for (char x : s) {
        if (x == '8') {
            ret = true;
        }
    }
    return ret;
}

int main() {
    int N;
    cin >> N;

    int ans = 0;
    for (int i = 1; i <= N; i++) {
        string si = to_string(i);
        if (is_include_8(si)) {
            ans++;
        }
    }
    cout << ans << endl;
}