#include <bits/stdc++.h>
using namespace std;
int P5, N, Ans;
int main() {
  cin >> N;
  P5 = N % 5;
  N -= P5;
  if (P5 == 0)
    Ans = N / 5;
  else
    Ans = N / 5 + 1;
  cout << Ans;
  return 0;
}
