#include <bits/stdc++.h>
using namespace std;

void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
}

int main() {
    fast_io();
    int x;
    cin >> x;
    int d[] = {2, 2, -1, -1, 2, -1, -1};
    int cur = 0, turn = 0, dist = 0;
    while (true) {
        if (cur == x) {
            cout << dist << endl;
            break;
        }
        cur += d[turn % 7];
        dist += abs(d[turn % 7]);

        turn++;
    }
}