#include <bits/stdc++.h>
using namespace std;
int main() {
  int count = 0;
  int x;
  cin >> x;
  while (x > 0) {
    if (x >= 5) {
      x -= 5;
      count++;
    } else if (x == 4) {
      x -= 4;
      count++;
    } else if (x == 3) {
      x -= 3;
      count++;
    } else if (x == 2) {
      x -= 2;
      count++;
    } else if (x == 1) {
      x--;
      count++;
    } else
      ;
  }
  cout << count << endl;
}
