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