class Program
    {
        List<int> multiple3 = new List<int>();
        List<int> multiple5 = new List<int>();
        List<int> doubles = new List<int>();
        int result = 0;

        public Program()
        {

        }

        public void Multiple3()
        {
            for (int i = 1; i < 1000; i++)
            {
                if (i % 3 == 0)
                {
                    multiple3.Add(i);
                }
            }
        }

        public void Multiple5()
        {
            for (int i = 1; i < 1000; i++)
            {
                if (i % 5 == 0)
                {
                    multiple5.Add(i);
                }
            }
        }

        public void Addition()
        {
            for (int i = 0; i < multiple3.Count; i++)
            {
                for (int j = 0; j < multiple5.Count; j++)
                {
                    if (multiple3[i] == multiple5[j])
                    {
                        doubles.Add(multiple3[i]);
                    }
                }
            }
            result = multiple3.Sum() + multiple5.Sum() - doubles.Sum();
            Console.WriteLine("{0}", result);
        }

        static void Main()
        {
            Program program = new Program();
            program.Multiple3();
            program.Multiple5();
            program.Addition();
            for (; ; )
            {

            }
        }
    }