#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,f=0,v;
	cin>>n;
	for(int m=1;m<n/2;m++){
		v=(n-2*m)*(n-2*m)*m;
		if(v>f) f=v;
	}
	cout<<f;
}

/**************************************************************
	Problem: 1350
	User: wangyiyang
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/