Two Numbers Sum

using System;

namespace КоледнаШапка
{
    class Program
    {
        static void Main(string[] args)
        {
            var startNum = int.Parse(Console.ReadLine());
            var endNum = int.Parse(Console.ReadLine());
            var magicNum = int.Parse(Console.ReadLine());

            var count = 0;

            for (int a = startNum; a >= endNum; a--)
            {
                for (int b = startNum; b >= endNum; b--)
                {
                    count++;

                    if (a + b == magicNum)
                    {
                        Console.WriteLine($"Combination N:{count} ({a} + {b} = {a + b})");
                        Environment.Exit(0);
                    }
                }
            }

            Console.WriteLine($"{count} combinations - neither equals {magicNum}");
        }
    }
}