#include <stdio.h>

int main()
{
 FILE *f,*g;
 int p,n=0,i,d5=0;
 f=fopen("fact.in","r");
 fscanf(f,"%d",&p);
 do
 {
  n+=5;
  i=n;
  while (i%5==0)
  {
   if (i%5==0) {i=i/5;++d5;};
  }
 }
 while (d5<p);
 if (p==0) n=1;
 else if (d5>p) n=-1;
 g=fopen("fact.out","w");
 fprintf(g,"%d",n);
 return 0;
}