#include <bits/stdc++.h>
using namespace std;
int main() {
  int a[5] = {1, 2, 3, 4, 5};
  int n;
  cin >> n;
  if (n <= 5) cout << 1;
  int x, y;
  if (n > 5) {
    x = n / 5;
    if (n % 5 == 0)
      cout << x;
    else
      cout << x + 1;
  }
  return 0;
}
