/*
TASK:minitime
LANG:C++
*/
#include<iostream>
using namespace std;
int main ()
{
    int n,mac[100],Br_Mac=0,mik[100],Br_Mik=0,raf=0,save=0,i,al=0;
      cin>>n;
      
    for(  i=2 ; i<n; i++ )
    {
         if( n/i + ( n/i + n%i ) ) {
              mac[Br_Mac]=n/i;Br_Mac++;
              mik[Br_Mik]=   n/i+n % i ; Br_Mik++;
              break;
              
              }
    }
    raf=Br_Mik+Br_Mac;al++;
    for(  i=0; i<raf-1; i++ ) {
              save=save + mac[i] + mik[i];
              al++;
              }
              al=al+1;
     if( ( ( save + raf ) % al )!=0 )cout<<n<<endl;       
     else  
      {
           if(  (save+raf) /al >n )
               cout<<   ( ( save + raf )/al ) / 2<<endl;
               else
                   cout<< ( ( save + raf )/al)*2<<endl;
     }
            
//system("pause");
}

