Problem3PrimesInGivenRange

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
class Problem3PrimesInGivenRange
{
    static bool IsPrime(int n)
    {
        bool isPrime = true;
        if (n >= 2)
        {
            for (int i = 2; i <= Math.Sqrt(n); i++)
            {
                if (n % i == 0)
                {
                    isPrime = false;
                    break;
                }
            }
        }
        else
        {
            isPrime = false;
        }
        return isPrime;
    }
    static List<int> FindPrimesInRange(int startNum, int endNum)
    {
        List<int> PrimesInRange = new List<int>();
        for (int i = startNum; i <= endNum; i++)
        {
            if (IsPrime(i) == true)
            {
                PrimesInRange.Add(i);
            }
        }
        return PrimesInRange;
    }
    static void Main()
    {
        while (true)
        {
            int startNum = int.Parse(Console.ReadLine());
            int endNum = int.Parse(Console.ReadLine());
            string toPrint = String.Join(", ",FindPrimesInRange(startNum, endNum));
            Console.WriteLine(toPrint);
        }
    }
}