using System;

public class Program

{

     static void nhapdulieu(out int a, out int b, out int c)

        {

            Console.WriteLine("nhap gio bat dau :");

            a = int.Parse(Console.ReadLine());

            Console.WriteLine("nhap gio ket thuc :");

            b = int.Parse(Console.ReadLine());

            Console.WriteLine("nhap so may :");

            c = int.Parse(Console.ReadLine());

        }

        static int tinhgio(int a, int b)

        {

            return (b - a);

        }

        static int sotiengio1(int a, int b, ref int h)

        {

            return (h * 2500);

        }

        static int sotiengio2(int a, int b, ref int h)

        {

            return (h * 3000);

        }

        static void Main(string[] args)

        {

            int a, b, c, h, g, v;

            nhapdulieu(out a, out b, out c);

            h = tinhgio(a, b);

            g = sotiengio1(a, b, ref h);

            v = sotiengio2(a, b, ref h);

            if (a < 6)

            {

                Console.WriteLine("vui long nhap lai :");

            }

            if (6 <= a && a <= 16)

            {

                Console.WriteLine("so tien choi dc = {0}", g);

            }

            if (a >= 17 && a <= 21)

            {

                Console.WriteLine("so tien choi dc = {0}", v);

            }

            if (6 <= b && b <= 16)

            {

                Console.WriteLine("so tien choi dc = {0}", g);

            }

            if (b >= 17 && b <= 21)

            {

                Console.WriteLine("so tien choi dc = {0}", v);

            }

            Console.WriteLine("so gio choi = {0}", h);

            Console.ReadLine();

        } 

}