#include <bits/stdc++.h>
using namespace std;
void solve() {
  int x;
  cin >> x;
  int my = 0;
  while (x != 0) {
    if (x >= 5) {
      my++;
      x = x - 5;
      continue;
    }
    if (x >= 4) {
      my++;
      x = x - 4;
      continue;
    }
    if (x >= 3) {
      my++;
      x = x - 3;
      continue;
    }
    if (x >= 2) {
      my++;
      x = x - 2;
      continue;
    }
    if (x >= 1) {
      my++;
      x = x - 1;
      continue;
    }
  }
  cout << my;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
  return 0;
}
