using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var arr = new int[] {-2,0,10,-19,4,6,-8};

        Console.WriteLine(CheckIfExist(arr));

    }

    public static bool CheckIfExist(int[] arr) 

    {        

        for(int i = 0; i < arr.Length; i++)

        {

            int n = arr[i];

            for(int j = 0; j < arr.Length; j++)

            {

                if(arr[j] == (n + n) && i != j)

                {

                    Console.WriteLine("arr[j] : " +  arr[j] + " (n + n) : " +  (n + n));

                    return true;

                }

            }

        }

        return false;

    }

}