using System;

class Program
{
    static void Main()
    {
        int a, b;
        Console.Write("Enter a: ");
        a = Convert.ToInt32(Console.ReadLine());
        Console.Write("Enter b: ");
        b = Convert.ToInt32(Console.ReadLine());

        if ((a < 0 && b < 0) || a == b || (a < 0 && b == 0) || (a == 0 && b < 0))
        {
            Console.WriteLine("a and b are both below zero, or equal to it, or equal to each other, or one of them is below zero and the other is 0");
        }
        else
        {
            if(a>b)
            {
                int tmp = a;
                a = b;
                b = tmp;
            }
            Console.WriteLine("If between a and b there are numbers, in binary form of which there are only four 1, then they will be displayed after this message");
            for (int i=a;i<=b;i++)
            {
                if (i < 0) continue;

                int count = 0;
                int temp = i;
                while (temp > 0)
                {
                    int temp1 = temp % 2;
                    if (temp1 == 1) count++;
                    temp /=2;
                }
                if (count == 4) Console.WriteLine(i);

            }
            Console.ReadKey();
        }
    }
}