#include <bits/stdc++.h>
#include <atcoder/all>

typedef unsigned long long ULLONG;
typedef long long LLONG;
static const LLONG MOD_NUM = 1000000007LL; //998244353LL;
static const LLONG INF_NUM = LLONG_MAX;
template<class _T> static void get(_T& a) {
	std::cin >> a;
}
template<class _T> static void get(_T& a, _T& b) {
	std::cin >> a >> b;
}
template<class _T> static void get(_T& a, _T& b, _T& c) {
	std::cin >> a >> b >> c;
}
template <class _T> static _T tp_abs(_T a) {
	if (a < (_T)0) {
		a *= (_T)-1;
	}
	return a;
}

static void task();

int main()
{
	task();
	fflush(stdout);
	return 0;
}

static void task()
{
	LLONG N;
	get(N);

	LLONG days = std::max(0LL, (N - 3LL)) * 5LL + std::min(N, 3LL);
	printf("%lld\n", days);
}