source_code: import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.List;
  
  
  public class IQTest {
  	public static void main(String args[]) throws Exception {
  		BufferedReader stdin =
  			new BufferedReader(new InputStreamReader(System.in));
  		String line;
  			line = stdin.readLine();
  			int n = Integer.parseInt(line);
  			line = stdin.readLine();
  			List even = new ArrayList();
  			List odd = new ArrayList();
  			String[] kk = line.split(" ");
  			for(int i=0;i<n;i++) {
  				if(Integer.parseInt(kk[i])%2==0)
  					even.add(i);
  				else
  					odd.add(i);
  			}
  			if(even.size()==1)
  				System.out.println((Integer)even.get(0)+1);
  			else
  				System.out.println((Integer)odd.get(0)+1);
  	}
  }
  