#include <stdio.h>

void main(void)
{
 FILE *in,*out;
 int s,q,k,aux,c,ok,i;
 long int p;
 in=fopen("fact.in","r");
 out=fopen("fact.out", "w");
 fscanf(in, "%d", &s);
 ok=1;
 i=1;p=1;
 while(ok)
 {
  p=p*i;
  aux=p;
  c=0;
  q=1;
  k=1;
  while(q)
  {
  k=k*10;
  if(aux%k==0) c++;
  else q=0;
  }

  if(c==s)
  {
   fprintf(out,"%d", i);
   ok=0;
  }
  i++;
 }
 fclose(out);

 }