#include <stdio.h>
long p,i;
long n,nc;
int main ()
{
FILE *in,*out;
in=fopen("fact.in","rt");
fscanf(in,"%ld",&p);
fclose(in);
n=0;
if (p)
do
{
n=n+5;
nc=n;
while (nc%5==0)
      {
      i++;
      nc=nc/5;
      }
} while (i<p);
else
   n=1;
out= fopen("fact.out","wt");
if (i<= p)
   fprintf(out,"%ld",n);
else
   fprintf(out,"-1");
fclose (out);
return 0;
}