#include <iostream>
#include <fstream>
using namespace std;
int main()
{  
 int p , suta=100 , n , i = 1 , nrzero = 0 , terminat= 0 ;
 int mia = 1000 , patratu = 25 ;
 int v[100];
 fstream f("fact.in",ios::in);
 f >> p ;
 f.close();
 n = p * 5 ;
  nrzero = p ; 
  while( n > patratu ) 
  {
   nrzero += i ;
   i++;
   patratu *= 5;
  }
  while(n > suta )
  {
   nrzero ++;
   suta += 100 ;
  }       
  while( n > mia )
  { 
    nrzero++;
    mia += 1000;     
  }
  fstream g("fact.out",ios::out );       
  if( n == patratu)
  {
   g<<"-1";
   terminat = 1 ;
  }
  for(i = 0 ; i < nrzero - p && !terminat ; i++)
  {
   n-=5;            
  }
  if( n == 0 )
  {
   g<<"1";   
   terminat = 1;
  }
     
 if(!terminat )g<<"N = "<<n;     
 return 0;
}