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