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