source_code: import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.List;
  import java.util.Scanner;
  
  public class A {
  	public static void main(String[] args) throws Exception {
  		Scanner scan = new Scanner(System.in);
  		int n = scan.nextInt();
  		List<Integer> list = new ArrayList<Integer>(), list2;
  		for (; n-- > 0;) {
  			list.add(scan.nextInt());
  		}
  		list2 = new ArrayList<Integer>(list);
  		Collections.sort(list2, new Comparator<Integer>() {
  			public int compare(Integer o1, Integer o2) {
  				return o1 % 2 - o2 % 2;
  			}
  		});
  		System.out.println(list.indexOf(list2.get(list2.get(1) % 2 > 0 ? 0
  				: list2.size() - 1)) + 1);
  	}
  }
  