#include<iostream>
using namespace std;
int main()
{
	int a,coin=0,coin2=0;
	cin>>a;
		if(a/11<1&&a/5<1)
		{
			cout<<a;
			return 0;
		}
		if(a/11<1&&a/5>=1)
		{
			cout<<a/5+a%5;
			return 0; 
		}
		coin2+=a/5;
		coin2+=a%5;
		coin+=a/11;
		a%=11;
		if(a>=5)
		{
			coin+=a/5;
			coin+=a%5;
			if(coin>=coin2) cout<<coin2;
			else cout<<coin;
			return 0;
		}
		else{
			coin+=a;
			if(coin>=coin2) cout<<coin2;
			else cout<<coin;
			return 0;
		}
}