AndreyAndBilliard

using System;
using System.Collections.Generic;
using System.Linq;

namespace AndreyAndBilliard
{

    class Customer
    {
        public string Name { get; set; }
        public Dictionary<string, int> Products { get; set; }

        public void AddProduct(Dictionary<string, int> productToAdd)
        {
            string productName = productToAdd.ElementAt(0).Key;
            int quantity = productToAdd.ElementAt(0).Value;
            if (!Products.ContainsKey(productName))
            {
                Products.Add(productName, quantity);
            }
            else
            {
                Products[productName] += quantity;
            }
        }

        public decimal GetCustomerBill(Dictionary<string, decimal> priceList)
        {
            decimal bill = 0.0m;
            foreach (var product in Products)
            {
                bill += product.Value * priceList[product.Key];
            }
            return bill;
        }
    }

    class Program
    {
        static void Main()
        {
            var priceList = GeneratePriceList(int.Parse(Console.ReadLine()));
            var customerList = new List<Customer>();
            AddClients(priceList, customerList);
            decimal totalBill = 0.0m;
            foreach (var customer in customerList.OrderBy(s => s.Name))
            {
                Console.WriteLine(customer.Name);
                foreach (var product in customer.Products)
                {
                    Console.WriteLine($"-- {product.Key} - {product.Value}");
                };
                decimal customerBill = customer.GetCustomerBill(priceList);
                totalBill += customerBill;
                Console.WriteLine($"Bill: {customerBill:F2}");
            }
            Console.WriteLine($"Total bill: {totalBill:F2}");
        }

        private static void AddClients(Dictionary<string, decimal> priceList, List<Customer> customerList)
        {
            string input = Console.ReadLine();
            while (input != "end of clients")
            {
                var splitted = ReadInput(input);
                if (priceList.ContainsKey(splitted[1]))
                {
                    var newCustomer = ReadCustomer(splitted);
                    if (!customerList.Any(s => s.Name == newCustomer.Name))
                    {
                        customerList.Add(newCustomer);
                    }
                    else
                    {
                        var productToAdd = newCustomer.Products;
                        foreach (var customer in customerList)
                        {
                            if (customer.Name == newCustomer.Name)
                            {
                                customer.AddProduct(newCustomer.Products);
                                break;
                            }
                        }
                    }
                }
                input = Console.ReadLine();
            }
        }

        private static Customer ReadCustomer(string[] splitted)
        {
            return new Customer
            {
                Name = splitted[0],
                Products = new Dictionary<string, int>() { { splitted[1], int.Parse(splitted[2]) } }
            };
        }

        private static string[] ReadInput(string input)
        {
            return input
                .Split(new char[] { '-', ',' }, StringSplitOptions.RemoveEmptyEntries);
        }

        private static Dictionary<string, decimal> GeneratePriceList(int n)
        {
            var priceList = new Dictionary<string, decimal>();
            for (int i = 0; i < n; i++)
            {
                var input = Console.ReadLine()
                    .Split(new char[] { '-' }, StringSplitOptions.RemoveEmptyEntries);
                priceList[input[0]] = decimal.Parse(input[1]);
            }
            return priceList;
        }
    }
}