AccountBalance

using System;

namespace AccountBalance
{
    class Program
    {
        static void Main(string[] args)
        {
            double balance = 0.0;
            string money = Console.ReadLine();

            while(money != "NoMoreMoney")
            {
                money = double.Parse(money);

                if (money < 0)
                {
                    Console.WriteLine("InvalidOperation!");
                    break;
                }

                balance += money;
            }
        }
    }
}