using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        int[] arr = new int[20];

        for(int i =0; i < 20; i++) {

            arr[i] = i;

        }

        int[] arrSet = randomSet(arr, 10);

        for (int i=0; i< 10; i++) {

            Console.Write(arrSet[i] + "|");

        }

    }

    public static int[] randomSet(int[] arr, int size) {

        int[] arrSet = new int[size];

        for(int i = 0; i < size; i++) {

            arrSet[i] = arr[i];

        }

        Random r = new Random();

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

            int positionToInsert = r.Next(0, size);

            arrSet[positionToInsert] = arr[i];

        }

        return arrSet;

    }

}