שאלה 4

        static void Main(string[] args)
        {
            int i, pupilnum, moneyperpupil, j , sum = 0;
            for (i = 0; i < 3; i++)
            {
                pupilnum = int.Parse(Console.ReadLine());
                moneyperpupil = int.Parse(Console.ReadLine());
                Console.WriteLine(pupilnum * moneyperpupil);
                sum = sum + (pupilnum * moneyperpupil);

            }
            Console.Write(sum);