Increasing 4 numbers

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


class Program
{
    static void Main()
    {

        int a = int.Parse(Console.ReadLine());
        int b = int.Parse(Console.ReadLine());
        bool c = false;
        for (int num1 = a; num1 <= b; num1++)
        {
            for (int num2 = a; num2 <= b; num2++)
            {
                for (int num3 = a; num3 <= b; num3++)
                {
                    for (int num4 = a; num4 <= b; num4++)
                    {
                        if (a<=num1 && num1<num2 && num2<num3 && num3<num4 && num4<=b)
                        {
                            Console.WriteLine(num1+" "+num2 + " " + num3 + " " + num4);

                        }
                        else
                        {
                            c = true;
                        }

                    }
                }
            }
        }//end of for
        if (c)
        {
            Console.WriteLine("No");
        }

    }
}