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