Convert

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

namespace Конзолен_конвертор_USD_към_BGN
{
    class Program
    {
        static void Main(string[] args)
        {
            var num = double.Parse(Console.ReadLine());
            var first = Console.ReadLine();
            var second = Console.ReadLine();

            if (first == "BGN")
            {
                if (second == "USD")

                    Console.WriteLine( Math.Round(num / 1.79549, 2));

                else if (second == "EUR")

                    Console.WriteLine( Math.Round(num / 1.95583, 2));

                else if (second == "GBP")

                    Console.WriteLine( Math.Round(num / 2.53405, 2));

            }
            if (first == "USD")
            {
                if (second == "BGN")

                    Console.WriteLine(Math.Round(num * 1.79549, 2));

                else if (second == "EUR")

                    Console.WriteLine(Math.Round(num * 1.79549 / 1.95583, 2));

                else if (second == "GBP")

                    Console.WriteLine(Math.Round(num * 1.79549 / 2.53405, 2));

            }
            if (first == "GBP")
            {
                if (second == "BGN")

                    Console.WriteLine(Math.Round(num * 2.53405 , 2));

                else if (second == "USD")

                    Console.WriteLine(Math.Round(num * 2.53405 / 1.79549, 2));

                else if (second == "EUR")

                    Console.WriteLine(Math.Round(num * 2.53405 / 1.95583 , 2));

            }
            if (first == "EUR")
            {
                if (second == "BGN")

                    Console.WriteLine(Math.Round(num * 1.95583, 2));

                else if (second == "USD")

                    Console.WriteLine(Math.Round(num * 1.95583 / 1.79549, 2));

                else if (second == "GBP")

                    Console.WriteLine(Math.Round(num * 1.95583 / 2.53405, 2));

            }
        }
    }
}