#include <bits/stdc++.h>
using namespace std;
int max(int n) {
  if (n >= 5)
    return 5;
  else if (n >= 4)
    return 4;
  else if (n >= 3)
    return 3;
  else if (n >= 2)
    return 2;
  else
    return 1;
}
int main() {
  int n, c = 0;
  cin >> n;
  while (n != 0) {
    n -= max(n);
    c++;
  }
  cout << c << "\n";
  return 0;
}
