#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,a,b,c=1,d=0;
	cin>>n;
	while(n>=c){
		a=c;
		while(a>0){
			b=a%10;
			a=a/10;
			if(b==8){
			    d++;
				}
			}
		c++;
		}
    cout<<d;	
}
	    

	    
	
 

/**************************************************************
	Problem: 1987
	User: lvrenxiang
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/