class program
{
    static void Main(string[] args)
    {
        Queue<int> shoppingList = new Queue<int>();

        FillQueue(shoppingList);
        ServeСlients(shoppingList);
    }

    private static void ServeСlients(Queue<int> shoppingList)
    {
        int score = 0;

        while (shoppingList.Count > 0)
        {
            Console.WriteLine($"Клиент заплатил {shoppingList.Peek()} рублей.");
            score += shoppingList.Dequeue();
            Console.WriteLine($"Сумма в кассе: {score}");
            Console.ReadLine();
            Console.Clear();
        }

        Console.WriteLine($"Сумма в кассе: {score}");
    }

    private static void FillQueue(Queue<int> shoppingList)
    {
        shoppingList.Enqueue(100);
        shoppingList.Enqueue(150);
        shoppingList.Enqueue(200);
        shoppingList.Enqueue(250);
        shoppingList.Enqueue(300);
    }
}