#include "iostream.h"

#include "conio.h"
#include "stdio.h"

int main()
{
     int n,a;
     cin>>n;
     a=1;
     for(int i=2;i<=n/2;i++)
     if(n%2==0)
     {
               cout<<"no";
               a=0;
               break;
               }
               if (a==1)
               cout<<"yes";
               cin>>n;
               return 0;
 }