#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,i,h=0,a,j,b;
	cin>>n;
	for(i=1;i<=n;i++){
		j=i;
		a=0;
		b=0;
		while(j!=0){
			a=j%10;
			j=j/10;
			b=b+a;
			if(b==10) h++;
		}
	}
	cout<<h;
}
/**************************************************************
	Problem: 1985
	User: linzihang
	Language: C++
	Result: Wrong Answer
****************************************************************/