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