Currency Converter

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

namespace CurrencyConverter
{
    class Program
    {
        static void Main(string[] args)
        {
            double amountToConvert = double.Parse(Console.ReadLine());
            string incomingCurrency = Console.ReadLine();
            string sourceCurrency = Console.ReadLine();
            double USD = 1.79549;
            double EUR = 1.95583;
            double GBP = 2.53405;

            double currentCurrency = 0;
            double totalSum = 0;
            if (incomingCurrency == "BGN")
            {
                currentCurrency = amountToConvert;
                if (sourceCurrency == "USD")
                {
                    totalSum = currentCurrency / USD;
                }
                else if (sourceCurrency == "EUR")
                {
                    totalSum = currentCurrency / EUR;
                }
                else if (sourceCurrency == "GBP")
                {
                    totalSum = currentCurrency / GBP;
                }
            }
            else if (incomingCurrency == "USD")
            {
                currentCurrency = amountToConvert * USD;
                if (sourceCurrency == "BGN")
                {
                    totalSum = currentCurrency;
                }
                else if (sourceCurrency == "EUR")
                {
                    totalSum = currentCurrency / EUR;
                }
                else if (sourceCurrency == "GBP")
                {
                    totalSum = currentCurrency / GBP;
                }
            }
            else if (incomingCurrency == "EUR")
            {
                currentCurrency = amountToConvert * EUR;
                if (sourceCurrency == "BGN")
                {
                    totalSum = currentCurrency;
                }
                else if (sourceCurrency == "USD")
                {
                    totalSum = currentCurrency / USD;
                }
                else if (sourceCurrency == "GBP")
                {
                    totalSum = currentCurrency / GBP;
                }
            }
            else if (incomingCurrency == "GBP")
            {
                currentCurrency = amountToConvert * GBP;
                if (sourceCurrency == "BGN")
                {
                    totalSum = currentCurrency;
                }
                else if (sourceCurrency == "USD")
                {
                    totalSum = currentCurrency / USD;
                }
                else if (sourceCurrency == "EUR")
                {
                    totalSum = currentCurrency / EUR;
                }
            }
            Console.WriteLine($"{totalSum:F2} {sourceCurrency}");
        }
    }
}