#include <bits/stdc++.h>

using namespace std;

int main() {
  int x;
  cin >> x;

  int now = 0, ans = 0, cnt = 0;
  vector<int> d {2, 2, -1, -1, 2, -1, -1};

  while (x != now) {
    int next = now + d[cnt % 7];
    ans += abs(d[cnt % 7]);
    ++cnt;

    now = next;
  }

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