source_code: import java.util.*;
  public class Main { 
      public static void main(String[] args) {
          Main iq = new Main();
          Scanner sc = new Scanner(System.in);
          int n;
          n = sc.nextInt();
          int[] naturalNumbers = new int[n];
          for (int i = 0; i < naturalNumbers.length; i++) {
              naturalNumbers[i] = sc.nextInt();
          }
          System.out.println(iq.diffInEvenness(n, naturalNumbers));          
      }
      
      public int diffInEvenness(int n, int[] naturalNumbers) {       
          int even, odd, lastEvenIndex, lastOddIndex;
          even = odd = lastEvenIndex = lastOddIndex = 0;
          for (int i = 0; i < naturalNumbers.length; i++) {
              if((naturalNumbers[i] % 2) == 0) {
                  even++;
                  lastEvenIndex = i + 1;
              }
              else {
                  odd++;
                  lastOddIndex = i + 1;
              }
          }
          return (even > odd ? lastOddIndex : lastEvenIndex);     
      }
  
  }