#include <bits/stdc++.h>
using namespace std;
int main(){
	int a,s,d,f,m,l,k=0;
	cin>>l;
	for(a=1;a<=l;a++){
		s=a%10;
		d=a/10%10;
		f=a/100;
		m=s+d+f;
		if(m==10){
		  k=k+1;	
		}
	}
	cout<<k<<endl;
}

/**************************************************************
	Problem: 1985
	User: tonghuawei
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2072 kb
****************************************************************/