SumPrimeNonPrime

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

namespace SumPrimeNonPrime
{

    class Program
    {
        static void Main(string[] args)
        {
            string command = string.Empty;
            int sumPrime = 0;
            int sumNonPrime = 0;
            int commandToInt = 0;
            int ifPrime = 0;


            while (command != "stop")


            {
                command = Console.ReadLine();
                if (command == "stop")
                {
                    Console.WriteLine($"Sum of all prime numbers is: {sumPrime}");
                    Console.WriteLine($"Sum of all non prime numbers is: {sumNonPrime}");
                }
                else
                {

                    commandToInt = int.Parse(command);
                    if (commandToInt < 0)
                    {
                        Console.WriteLine("Number is negative.");
                    }

                    else
                    {
                        for (int i = 1; i <= commandToInt; i++)
                        {
                            if (commandToInt % i == 0)
                            {
                                ifPrime++;
                            }

                        }
                        if (ifPrime == 2)
                        {
                            sumPrime = sumPrime + commandToInt;

                        }
                        else
                        {
                            sumNonPrime = sumNonPrime + commandToInt;

                        }
                        ifPrime = 0;
                    }
                }


            }

        }
    }
}