#include <bits/stdc++.h>
using namespace std;
int main() {
  int pos;
  double f;
  cin >> pos;
  if (pos >= 5) {
    f = pos / 5;
    if (pos % 5 != 0) f = floor(f) + 1;
  } else
    f = 1;
  cout << f;
}
