using System;

using System.Collections.Generic;

​

public static class Program

{       

    static Func<long, string> remainder = t => t > 0 ? " " + ToEN(t) : "";

    public static string ToEN(this long val, double d = 20, long th = 20)

    {

        switch ((long)d)

        {

            case 20:   return val >= d ? ToEN(val, 1e2)             : en[val];

            case 100:  return val >= d ? ToEN(val, 1e3, 100)        : en[val / 10 * 10] + remainder(val % 10);

            default:   return val >= d ? ToEN(val, d * 1e3,(long)d) : ToEN(val / th) + " " + en[th] + remainder(val % th);

        }

    }

    public static void Main(string[] args)

    {

        Console.WriteLine(long.MaxValue.ToEN());

        Console.WriteLine((long.MaxValue / 2).ToEN());      

        Console.WriteLine(66666662L.ToEN());        

    }

    static readonly Dictionary<long, string> en = new Dictionary<long, string> {

        {0 , "zero"},

        {1 , "one"},

        {2 , "two"},

        {3 , "three"},

        {4 , "four"},

        {5 , "five"},

        {6 , "six"},

        {7 , "seven"},

        {8 , "eight"},

        {9 , "nine"},

        {10, "ten"},

        {11, "eleven"},

        {12, "twelve"},

        {13, "thirteen"},

        {14, "fourteen"},

        {15, "fifteen"},

        {16, "sixteen"},

        {17, "seventeen"},

        {18, "eighteen"},

        {19, "nineteen"},

        {20, "twenty"},

        {30, "thirty"},

        {40, "forty"},

        {50, "fifty"},

        {60, "sixty"},

        {70, "seventy"},

        {80, "eighty"},

        {90, "ninety"},

        {100,"hundred"},

        {(long)1e3,  "thousand"},

        {(long)1e6,  "million"},

        {(long)1e9,  "billion"},

        {(long)1e12, "trillion"},

        {(long)1e15, "quadrillion"},

        {(long)1e18, "quintillion"}

    };

}