#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000005
#define Inf64 1000000000000000001LL

int main(){
	
	int n;
	cin>>n;
	
	int ans = 0;
	rep(i,n+1){
		string  t = to_string(i);
		bool f = false;
		rep(j,t.size()){
			if(t[j]=='8')f = true;
		}
		if(!f)continue;
		ans++;
	}
	cout<<ans<<endl;
	
}