using System;

public class Program

{

    static int[] Gen(int len)

    {

        int [] a = new int[len];

        var rnd = new Random(100500);

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

        {

            a[i] = rnd.Next(2);

        }

        return a;

    }

    static int Calc(int[] a)

    {

        int sum = 0;

        int ind = 0;

        for (int i = a.Length-1; i >= 0; i--)

        {

            if (a[i] == 1)

            {

                sum += (int)Math.Pow(2, ind);

            }

            ind++;

        }

        return sum;

    }

    static void Print(int[] a)

    {

        Console.WriteLine(string.Join("", a));

    }

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var a = Gen(4);

        Print(a);

        var num = Calc(a);

        Console.WriteLine(num);

    }

}