#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,i,j,h=0,a;
	cin>>n;
	for(i=1;i<=n;i++){
		j=i;
		a=0;
		while(j!=0){
			a=j%10;
			j=j/10;
			if(a==8) h++;	
		}
	}
	cout<<h;
}
/**************************************************************
	Problem: 1987
	User: linzihang
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/