#include<stdio.h>
int main()
{unsigned long n;
freopen("fact.in","r",stdin);
freopen("fact.out","w",stdout);
scanf("%lu",&n);
if(n==0)
	printf("%lu","1");
else
	if(n%5==0)
		printf("%lu","-1");
	else
		printf("%lu",(n-(n/5))*5);
return 0;
}