#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>

using namespace std;

long long n,f[20];

int main()
{
	freopen("xcoins.in","r",stdin);
	freopen("xcoins.out","w",stdout);
	cin>>n;
	f[5]=1;
	f[6]=6;
	f[7]=3;
	f[8]=4;
	f[9]=3;
	f[10]=2;
	f[11]=3;
	f[12]=4;
	f[13]=3;
	f[14]=4;
	f[15]=3;
	if (n<=15) cout<<f[n]<<endl;
	else
	{	
		if (n%5==0) 
		{
			cout<<n/5<<endl;
			return 0;
		}
		if ((n-((n/5)*5))%2==0) cout<<n/5+2;
		else cout<<n/5+1<<endl;
	}
	return 0;
}