#include<bits/stdc++.h>
using namespace std;
int main() {
    int n,g,s,b,q,gs=0;
    cin>>n;
    for(int i=1;i<=n;i++){
        g=i%10;
        s=i/10%10;
        b=i/100%10;
        q=i/1000;
        if(g==8) gs++;
        if(s==8) gs++;
        if(b==8) gs++;
        if(q==8) gs++;
    }
    cout<<gs;
}
/**************************************************************
	Problem: 1987
	User: yangjunwen
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/