#include <iostream>
using namespace std;

int main() {
	int D;
	cin >> D;
	
	if(( (D % 2) ) || ( D < 4 ) ){
		cout << 0 << endl;
		return 0;
	}
	
	int A;
	
	if(D%4)A = (D/4)*(D/4+1);
	else A = (D*D)/16;
 
	cout << A << endl;
	
	
	return 0;
}