#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  int ans = 1;
  while (true){
    N--;
    if (ans % 7 == 0){
      N += 6;
    }
    if (N == 0){
      cout << ans << endl;
      break;
    }
    ans++;
  }
}