Numbers-Exam2020

using System;
using System.Collections.Generic;
using System.Linq;

namespace Lists
{
    class Program
    {
        static int DigitSum(int number)
        {
            int sum = 0;
            while (number != 0)
            {
                sum += number % 10;
                number /= 10;
            }
            return sum;
        }
        static void Main(string[] args)
        {
            int[] numbers = Console.ReadLine()
                            .Split(',')
                            .Select(n => int.Parse(n))
                            .ToArray();
            List<int> gr1 = new List<int>();
            List<int> gr2 = new List<int>();
            List<int> gr3 = new List<int>();
            List<int> gr4 = new List<int>();

            foreach (var item in numbers)
            {
                if (item % 10 == 4 || item % 10 == 2)
                {
                    gr1.Add(item);
                }
                else if (item % 10 == 5 || item % 10 == 7)
                {
                    gr2.Add(item);
                }
                if (DigitSum(item) % 10 == 3)
                {
                    gr3.Add(item);
                }
                else if (DigitSum(item) % 10 == 6)
                {
                    gr4.Add(item);
                }
            }
            Console.WriteLine(string.Join(",", gr1));
            Console.WriteLine(string.Join(",", gr2));
            Console.WriteLine(string.Join(",", gr3));
            Console.WriteLine(string.Join(",", gr4));
        }
    }
}