#include<iostream>

int main()
{
	int x, S;
	std::cin >> x;

	S = x * x * x;
	std::cout << S << std::endl;

	return 0;
}
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <set>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define reps(i, s, n) for (int i = s; i < (int)(n); i++)
#define out(x) cout << x << endl
#define INF 1000000;
#include <map>
#include <math.h>
 
using ll = long long;
using namespace std;

ll n, k;
const ll mod = 1000000007;

int main(){
    int x;
    cin >> x;
    out(x/3);
}
