source_code: import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.io.StreamTokenizer;
  import java.util.ArrayList;
  
  public class A {
  	private static StreamTokenizer in;
  	private static PrintWriter out;
  
  	private static int nextInt() throws Exception {
  		in.nextToken();
  		return (int) in.nval;
  	}
  
  	private static String nextString() throws Exception {
  		in.nextToken();
  		return in.sval;
  	}
  
  	public static void main(String[] args) throws Exception {
  		in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
  		out = new PrintWriter(System.out);
  		
  		ArrayList<Integer> p = new ArrayList<Integer>();
  		ArrayList<Integer> o = new ArrayList<Integer>();
  		
  		int n = nextInt();
  		for (int i=0; i<n; i++) {
  			int a = nextInt();
  			if (a % 2 == 0) p.add(i+1);
  			else o.add(i+1);
  		}
  		
  		if (p.size() < o.size()) out.println(p.get(0));
  		else out.println(o.get(0));
  
  		out.flush();
  
  	}
  }