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

int main(){
  int X;
  cin >> X;
  
  int dx[7] = {2, 2, -1, -1, 2, -1, -1};
  int ans = 0, cx = 0;
  
  while(true){
    for(int i = 0; i < 7; i++){
      cx += dx[i];
      ans += abs(dx[i]);
      if(cx == X){
        cout << ans;
        return 0;
      }
    }
  }
}