#include <stdio.h>   
  
int main()   
{   
 FILE *f,*g;   
 int p,n=0,i,d5=0;   
 f=fopen("fact.in","r");   
 fscanf(f,"%d",&p);   
 fclose(f);   
 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);   
 fclose(g);   
 return 0;   
}