#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 5;
const int inf = 1e9 + 7;
long long mod = 998244353;
int main(void) {
  int x, ans = 0, i = 5;
  scanf("%d", &x);
  while (x != 0) {
    int t;
    t = x / i;
    ans += t;
    x -= t * i;
    i--;
  }
  printf("%d\n", ans);
  return 0;
}
