#include<stdio.h>
long p;
int a[20000];
int main()
{ freopen("fact.in","r",stdin);
  freopen("fact.out","w",stdout);
  scanf("%d",p);
  a[1]=5;
  for(long i=2;i<=20000;i++)
     { a[i]=a[i-1]+5;
       if(i%6==0)
	  { a[i]=a[i-1];
	    a[i-1]=0;
	  }
     }
  int j=-1;
  if(a[p]!=0) printf("%d",a[p]);
  else printf("%d",j);
  return 0;
}