#include <iostream>
#include <cstdlib>
#include <cstdio>

using namespace std;

long long n,x;
long long ans;

int main()
{
	freopen("xcoins.in","r",stdin);
	freopen("xcoins.out","w",stdout);
	scanf("%d",&n);
	if (n<=10)
	{
		if (n==5) ans=1;
		if (n==6) ans=6;
		if (n==7) ans=3;
		if (n==8) ans=4;
		if (n==9) ans=3;
		if (n==10) ans=2;
	}
	else
	{
		ans=n/5-2;
		x=n%5;
		if (x==1) ans=ans+3;
		if (x==2) ans=ans+4;
		if (x==3) ans=ans+3;
		if (x==4) ans=ans+4;
		if (x==0) ans=ans+2;
	}
	printf("%d\n",ans);
}