source_code: import java.io.*;
  
  public class Main 
  {
      public static void main(String []args)throws Exception
      {
          BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
          int n=0;
          n=Integer.parseInt(br.readLine());
          String inp="";
          inp=br.readLine();
          int no[]=new int[n];
          String tinp[]=inp.split(" ");
          for(int i=0;i<n;i++)
          {
              no[i]=Integer.parseInt(tinp[i]);
          }
          int eve=0,odd=0;
          for(int i=0;i<3;i++)
          {
              int rem=no[i]%2;
              if(rem==0)
                  eve++;
              else
                  odd++;
          }
                 if(eve>1)
                 {
                     for(int i=0;i<n;i++)
                     {
                         if(no[i]%2==1)
                         {
                             System.out.println(i+1);
                             break;
                         }
                     }
                 }
                 else
                 {
                       for(int i=0;i<n;i++)
                        {
                            if(no[i]%2==0)
                            {
                             System.out.println(i+1);
                             break;
                            }
                        }
              
                 }
                  
  
  }
  }
  