Nested.Loop.Exercises-06.Prime.NonPrime

using System;

namespace _06.SumPrimeNonPrime
{
    class Program
    {
        static void Main(string[] args)
        {
            string command = Console.ReadLine();
            int primeSum = 0;
            int nonprimeSum = 0;


            while (command != "stop")
            {
                int number = int.Parse(command);
                bool checkPrime = true;
                if (number < 0)
                {
                    Console.WriteLine("Number is negative.");
                    command = Console.ReadLine();
                    continue;
                }
                if (number == 1)
                {
                    primeSum+=number;
                    command = Console.ReadLine();
                    continue;
                }

                for (int i = 2; i <= 9; i++)
                {
                    if (number % i == 0 && number !=i)
                    {
                        nonprimeSum+=number;
                        checkPrime = false;
                        break;
                    }
                }

                if (checkPrime == true)
                {
                    primeSum += number;
                }

                command = Console.ReadLine();
            }
            Console.WriteLine($"Sum of all prime numbers is: {primeSum}");
            Console.WriteLine($"Sum of all non prime numbers is: {nonprimeSum}");


        }
    }
}