HM 2_4

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HomeWorck_8_3
{
    class Program
    {
        static void Main(string[] args)
        {
            Random rand = new Random();
            int number = rand.Next(100);
            int sum = 0;

            if (number == 0) {
                sum = number;
            }
            else
            {
                for (int counter = 0; counter < number; counter++)
                {
                    if ((counter % 3) == 0)
                    {
                        sum += counter;
                    }
                    else if ((counter % 5) == 0)
                    {
                        sum += counter;
                    }
                }
            }

            Console.WriteLine(sum);
            Console.ReadKey();
        }
    }
}