#include<fstream.h>
fstream f("fact.in",ios::in);
fstream g("fact.out",ios::out);
void main(){
unsigned long p,n,n2,n5;
f>>p;
n2=0;
n5=0;
int gasit,exista;
unsigned long c=1,aux;
gasit=0;
while(gasit==0)
   { c++;
    aux=c;
    while(aux%2==0)
     {
      n2++;
      aux/=2;
      }
    while(aux%5==0)
     {
      n5++;
      aux/=5;
      }
     if(n2>p&&n5>p)
	{exista=0;
	gasit=1;
	}
     else
       if(n2==p&&n5>p || n2>p&&n5==p)
	    {
	     gasit=1;
   }         exista=1;
   }
if(exista)
  g<<c;
else
 g<<-1;
g.close();
}