#include <bits/stdc++.h>
using namespace std;
int main() {
  int step = 0, a;
  const int one = 1, two = 2, three = 3, four = 4, five = 5;
  cin >> a;
  step += a / five;
  a %= five;
  step += a / four;
  a %= four;
  step += a / three;
  a %= three;
  step += a / two;
  a %= two;
  step += a / one;
  a %= one;
  cout << step;
  return 0;
}
