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