#include <bits/stdc++.h>
using namespace std;
const long long M = 1e9 + 7;
void solve() {
  long long n, k, i, p, q, r, count = 0, j, flag, ans = 0;
  cin >> n;
  cout << (n + 4) / 5 << "\n";
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin.tie(0);
  cout.tie(0);
  long long t;
  t = 1;
  while (t--) solve();
  return 0;
}
