#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: wengsihan
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/