#include<iostream>
#include<fstream>
int main()
{
	int i,t=0,m=0,p;
	ifstream f("fac.in");
	ofstream g("fac.out");
	f>>p;
	if(p==0)
		g<<1;
	else
	{
	for(i=1;i<=p;i++)
	{	
		t++;
		if(i%5==0)
			{	
				i++;
				t++;
				m=m+1;
			}	
	}
	if(p%6==5)
		g<<-1;
	else 
	g<<(t-m)*5;
	}
	return 0;
}