#include <iostream>
using namespace std;

int main(void) {
	int n;	cin >> n;

	int d[7] = { 2,2,-1,-1,2,-1,-1 };
	int i = 0, now = 0, ans = 0;
	while (now != n) {
		now += d[i];
		ans += abs(d[i]);
		i++;	i %= 7;
	}

	cout << ans << endl;
	return 0;
}