source_code: import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.Scanner;
  
  public class Main {
      
      public static void main(String[] args) throws NumberFormatException, IOException {
          Scanner sc = new Scanner(new InputStreamReader(System.in));
          int n = sc.nextInt(),even = 0,odd = 0,evI = 0,OdI = 0;      
          for (int i = 0; i < n; i++) {
              if(sc.nextInt()%2 == 1){
                  odd++;
                  OdI = i+1;
              }else{
                  even++;
                  evI = i+1; 
              }
          }
          if(even < odd)
              System.out.println(evI);
          else
              System.out.println(OdI);
          
      }
  }
  