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

        string sum = "sum";
        string exit = "exit";
        bool isWorking = true;

        while (isWorking)
        {
            string userInput = Console.ReadLine();

            if (userInput == sum)
            {
                Console.WriteLine(numbers.Sum());
            }
            else if (userInput == exit)
            {
                isWorking = false;
            }
            else
            {
                numbers.Add(Convert.ToInt32(userInput));
                Console.Clear();
            }
        }
    }
}