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

	    
	
 

/**************************************************************
	Problem: 1985
	User: lvrenxiang
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/