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

int main() {
  int x;
  cin >> x;
  vector<int> moves{2, 2, -1, -1, 2, -1, -1};
  int idx = 0;
  int cur = 0;
  int sum = 0;
  while (cur != x) {
    cur += moves[idx % moves.size()];
    sum += abs(moves[idx % moves.size()]);
    idx++;
  }
  cout << sum << '\n';
  return 0;
}