#include<fstream>
using namespace std;
int main()
{long a,p=0,n,i,pb=0,j;
ifstream f("fact.in");
ofstream g("fact.out");
f>>p;
if(p<5)
{if(p==0)
	g<<0;
if(p==1)
	g<<5;
if(p==2)
	g<<10;
if(p==3)
	g<<15;
if(p==4)
	g<<20;}
else
{
pb=0;
i=0;
while(pb<p)
{i=i+5;
j=i;
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
if(j%5==0)
{pb=pb+1;
j=j/5;}
}
if(pb==p)
g<<i;
else
g<<-1;}
f.close();
g.close();
return 0;}