switchcasevariant

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

namespace Currency_Converter
{
    class Program
    {
        static void Main(string[] args)
        {
            var sum = double.Parse(Console.ReadLine());
            var inputCurrency = Console.ReadLine();
            var outputCurrency = Console.ReadLine();
            double result = 0;

            switch (inputCurrency)
            {
                case "BGN":
                    switch (outputCurrency)
                    {
                        case "BGN":
                            result = sum;
                            break;
                        case "USD":
                            result = sum / 1.79549;
                            break;
                        case "EUR":
                            result = sum / 1.95583;
                            break;
                        case "GBP":
                            result = sum / 2.53405;
                            break;
                    }
                    break;
                case "USD":
                    switch (outputCurrency)
                    {
                        case "BGN":
                            result = sum * 1.79549;
                            break;
                        case "USD":
                            result = sum;
                            break;
                        case "EUR":
                            result = sum * 1.79549 / 1.95583;
                            break;
                        case "GBP":
                            result = sum * 1.79549 / 2.53405;
                            break;
                    }
                    break;
                case "EUR":
                    switch (outputCurrency)
                    {
                        case "BGN":
                            result = sum * 1.95583;
                            break;
                        case "USD":
                            result = sum * 1.95583 / 1.79549;
                            break;
                        case "EUR":
                            result = sum;
                            break;
                        case "GBP":
                            result = sum * 1.95583 / 2.53405;
                            break;
                    }
                    break;
                case "GBP":
                    switch (outputCurrency)
                    {
                        case "BGN":
                            result = sum * 2.53405;
                            break;
                        case "USD":
                            result = sum * 2.53405 / 1.79549;
                            break;
                        case "EUR":
                            result = sum * 2.53405 / 1.95583;
                            break;
                        case "GBP":
                            result = sum;
                            break;
                    }
                    break;
            }
            Console.WriteLine($"{Math.Round(result, 2)} {outputCurrency}");
        }
    }
}