#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,i,j,s=0;
	cin>>n;
	for(i=1;i<=n-1;i++){
		for(j=i+1;j<=n;j++){
			if((i+j)%3==0||(i+j)%7==0){
				s++;
			}
		}
	}
	cout<<s;
	return 0;
}

/**************************************************************
	Problem: 1086
	User: zzz
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/