#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  if (n <= 5) {
    cout << 1;
  } else {
    if (n % 10 == 0 || n % 5 == 0) {
      cout << n / 5;
    } else
      cout << n / 5 + 1;
  }
  return 0;
}
