#include <bits/stdc++.h>
using namespace std;
int main() {
  int x;
  cin >> x;
  if (x <= 5)
    cout << 1 << endl;
  else if (x % 5 == 0)
    cout << x / 5 << endl;
  else
    cout << (x / 5) + 1 << endl;
  return 0;
}
