#include<bits/stdc++.h>
using namespace std;
int n,a[25],s=0;
int main(){
cin>>n;
for(int i=1;i<=10;i++){
   n=n+30;
   if(n>=a[i]) s++;
	
}
cout<<s;


return 0;	


} 
/**************************************************************
	Problem: 1388
	User: wangyousi
	Language: C++
	Result: Wrong Answer
****************************************************************/