Currency Converter with switches

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

namespace Currency_Converter_with_switches
{
    class Program
    {
        static void Main(string[] args)
        {

                decimal amount = decimal.Parse(Console.ReadLine());
                string currencyOne = Console.ReadLine();
                string currencyTwo = Console.ReadLine();
                decimal convertionOne = new decimal();
                decimal convertionTwo = new decimal();
                decimal BGN = 1;
                decimal USD = 1.79549m;
                decimal EUR = 1.95583m;
                decimal GBP = 2.53405m;
                switch (currencyOne)
                {
                    case "BGN":
                        convertionOne = amount * BGN;
                        break;
                    case "USD":
                        convertionOne = amount * USD;
                        break;
                    case "EUR":
                        convertionOne = amount * EUR;
                        break;
                    case "GBP":
                        convertionOne = amount * GBP;
                        break;
                }
                switch (currencyTwo)
                {
                    case "BGN":
                        convertionTwo = convertionOne / BGN;
                        break;
                    case "USD":
                        convertionTwo = convertionOne / USD;
                        break;
                    case "EUR":
                        convertionTwo = convertionOne / EUR;
                        break;
                    case "GBP":
                        convertionTwo = convertionOne / GBP;
                        break;
                }
                Console.WriteLine(Math.Round(convertionTwo, 2));

    }
    }
}