#include <bits/stdc++.h>
using namespace std;
int ans = 1e9;
map<int, int> mp;
int dfs(int u, int tot) {
	if (u < 0) return 1000000000;
	else if (u == 0) {
		return mp[u] = tot;
	}
	if (mp[u] != 0) return mp[u];
	return mp[u] = min(dfs(u - 1, tot + 1), min(dfs(u - 5, tot + 1), dfs(u - 11, tot + 1)));
}
int main()
{
	int n;
	cin >> n;
	cout << dfs(n, 0);
	return 0;
}