source_code: import java.io.*;
  import java.util.*;
  
  public class Main implements Runnable {
  	private BufferedReader in;
  	private PrintWriter out;
  	private StringTokenizer st;
  	
  	private void eat(String line)
  	{
  		st = new StringTokenizer(line);
  	}
  	
  	private String next() throws IOException
  	{
  		while(!st.hasMoreTokens()) {
  			String line = in.readLine();
  			if(line == null)
  				return null;
  			eat(line);
  		}
  		return st.nextToken();
  	}
  	
  	private int nextInt() throws IOException
  	{
  		return Integer.parseInt(next());
  	}
  	
  	public void run()
  	{
  		try {
  			in = new BufferedReader(new InputStreamReader(System.in));
  			out = new PrintWriter(new OutputStreamWriter(System.out));
  			eat("");
  			
  			go();
  			
  			out.close();
  		} catch(Exception e) {
  			e.printStackTrace();
  			System.exit(-1);
  		}
  	}
  	
  	public static void main(String[] args)
  	{
  		new Thread(new Main()).start();
  	}
  	
  	public void go() throws IOException
  	{
  		int n = nextInt();
  		int[] v = new int[n], count = new int[2];
  		for(int i = 0; i < n; ++i) {
  			v[i] = nextInt();
  			++count[v[i] % 2];
  		}
  		int residue = count[0] == 1 ? 0 : 1;
  		for(int i = 0; i < n; ++i)
  			if(v[i] % 2 == residue)
  				out.println(i + 1);
  	}
  }
  