#include<bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define reps(i,s,n) for(int i=(int)(s);i<(int)(n);i++)
const ll mod = 1e9 + 7;
const int INF = 1e9;

int main() {
	cin.sync_with_stdio(false);
	int N;
	cin >> N;
	ll k = N / 8+1;
	ll x = N% 7;
	int m[8] = {0,0,1,0,3,2,3,7};
	ll ans = k*m[x];
	ans += (k - 1)*(7 - x);
	cout << ans << endl;


	return 0;
}