#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,g,s,b,q,h=0;
    cin>>n;
    for(int i=1;i<=n;i++){
        g=i%10;
        s=i/10%10;
        b=i/100;
        q=g+s+b;
        if(q==10){
            h++;
        }
    }
    cout<<h;
}
/**************************************************************
	Problem: 1985
	User: yangjunwen
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/