#include "iostream"
using namespace std;

long long int N;
int z_num[16] = { 0,0,0,2,2,4,6,6,6,8,10,10,12,12,12,16 };
long long int ans;

int main() {
	cin >> N;
	ans += N / 15 * z_num[15];
	ans += z_num[N % 15];
	cout << ans << "\n";
	return 0;
}