source_code: import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.io.StreamTokenizer;
  
  
  public class Main {
  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);
  int n = nextInt();
  byte f = (byte)nextInt();
  byte s = (byte)nextInt();
  byte t = (byte)nextInt();
  boolean bf = false;
  boolean bs = false;
  boolean bt = false;
  if((f&1) == 0){bf = true;}
  if((s&1) == 0){bs = true;}
  if((t&1) == 0){bt = true;}
  //System.out.println(bf+""+bs+""+bt);
  if((!bf)&&bs&&bt){System.out.println(1);return;}
  if(bf&&(!bs)&&bt){System.out.println(2);return;}
  if(bf&&bs&&(!bt)){System.out.println(3);return;}
  if(bf&&!bs&&!bt){System.out.println(1);return;}
  if(!bf&&bs&&!bt){System.out.println(2);return;}
  if(!bf&&!bs&&bt){System.out.println(3);return;}
  for(int i = 4; i<=n; i++){
  byte g = (byte) nextInt();
  if(((g+f)&1) == 1){System.out.println(i); return;}
  }
  
  
  
  out.flush();
  }
  }