#include <bits/stdc++.h>
using namespace std;
int dis = 0;
int mv = 0;
int is_there(int n) {
  if (dis + 5 <= n)
    dis += 5;
  else if (dis + 4 <= n)
    dis += 4;
  else if (dis + 3 <= n)
    dis += 3;
  else if (dis + 2 <= n)
    dis += 2;
  else if (dis + 1 <= n)
    dis += 1;
  mv += 1;
  if (dis == n) return mv;
  is_there(n);
}
int main() {
  int n;
  scanf("%u", &n);
  cout << is_there(n);
  return 0;
}
