GBP MISTAKE

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

namespace testtttt
{
    class Program
    {
        static void Main(string[] args)
        {
            double sum = double.Parse(Console.ReadLine());
            string input_cur = Console.ReadLine();
            string output_cur = Console.ReadLine();

            if (input_cur == "BGN" && output_cur == "USD")
                Console.WriteLine("{0:F2} USD", sum * 1 / 1.79549);
            else if (input_cur == "BGN" && output_cur == "EUR")
                Console.WriteLine("{0:F2} EUR", sum * 1 / 1.95583);
            else if (input_cur == "BGN" && output_cur == "GBP")
                Console.WriteLine("{0:F2} GBP", sum * 1 / 2.53405);

            else if (input_cur == "USD" && output_cur == "BGN")
                Console.WriteLine("{0:F2} BGN", sum * 1.79549);
            else if (input_cur == "USD" && output_cur == "EUR")
                Console.WriteLine("{0:F2} EUR", sum * 1.79549 / 1.95583);
            else if (input_cur == "USD" && output_cur == "GBP")
                Console.WriteLine("{0:F2} GBP", sum * 1.79549 / 2.53405);

            else if (input_cur == "EUR" && output_cur == "BGN")
                Console.WriteLine("{0:F2} GBN", sum * 1.95583);
            else if (input_cur == "EUR" && output_cur == "USD")
                Console.WriteLine("{0:F2} USD", sum * 1.79549 / 1.95583);
            else if (input_cur == "EUR" && output_cur == "GBP")
                Console.WriteLine("{0:F2} GBP", sum * 1.95583 / 2.53405);

            else if (input_cur == "GBP" && output_cur == "BGN")
                Console.WriteLine("{0:F2} BGN", sum * 1 / 2.53405);
            else if (input_cur == "GBP" && output_cur == "USD")
                Console.WriteLine("{0:F2} USD", sum * 2.53405 / 1.79549);
            else if (input_cur == "GBP" && output_cur == "EUR")
                Console.WriteLine("{0:F2} EUR", sum * 1.95583 / 2.53405);
        }
    }
}