#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,i,j,z,s=0;
	cin>>n;
	for(i=1;i<=n*i/3;i++){
		for(j=i;j<=n*1/2;j++){
			z=n-i-j;
			if(((z==j&&j!=i)||z>j)&&i+j>z&&i+z>j&&j+z>i&&i+j+z==n){
				s++;
			}
		}
	}
	cout<<s;
	return 0;
}

/**************************************************************
	Problem: 1079
	User: zzz
	Language: C++
	Result: Accepted
	Time:151 ms
	Memory:2072 kb
****************************************************************/