vending machine

using System;

namespace whileloop
{
    class Program
    {
        static void Main()
        {
            string command = Console.ReadLine();
            double coinsSum = 0;

            while (command != "Start")
            {
                double coins = double.Parse(command);

                if (coins != 0.1 && coins != 0.2 && coins != 0.5 && coins != 1.0 && coins != 2.0)
                {
                    Console.WriteLine($"Cannot accept {coins}");
                }
                else
                {
                    coinsSum += coins;
                }



                command = Console.ReadLine();
            }

            string input = Console.ReadLine();
            double price = 0;

            while (input != "End")
            {
                if (input == "Nuts")
                {
                    price = 2.0;

                    if (price <= coinsSum)
                    {
                        Console.WriteLine("Purchased nuts");
                        coinsSum -= price;
                    }
                    else
                    {
                        Console.WriteLine("Sorry, not enough money.");
                    }

                }
                else if (input == "Water")
                {
                    price = 0.7;

                    if (price <= coinsSum)
                    {
                        Console.WriteLine("Purchased water");
                        coinsSum -= price;
                    }
                    else
                    {
                        Console.WriteLine("Sorry, not enough money.");
                    }

                }
                else if (input == "Crisps")
                {
                    price = 1.5;

                    if (price <= coinsSum)
                    {
                        Console.WriteLine("Purchased crisps");
                        coinsSum -= price;
                    }
                    else
                    {
                        Console.WriteLine("Sorry, not enough money.");

                    }

                }
                else if (input == "Soda")
                {
                    price = 0.8;

                    if (price <= coinsSum)
                    {
                        Console.WriteLine("Purchased soda");
                        coinsSum -= price;
                    }
                    else
                    {
                        Console.WriteLine("Sorry, not enough money.");

                    }

                }
                else if (input == "Coke")
                {
                    price = 1.0;

                    if (price <= coinsSum)
                    {
                        Console.WriteLine("Purchased coke");
                        coinsSum -= price;
                    }
                    else
                    {
                        Console.WriteLine("Sorry, not enough money.");
                    }

                }
                else
                {
                    Console.WriteLine("Invalid product");
                }

                input = Console.ReadLine();
            }

            Console.WriteLine($"Change: {coinsSum:f2}");
        }
    }
}