[C#] Prime Checker

using System;
namespace PrimeChecker
{
    class Program
    {
        static void Main(string[] args)
        {
            long input = long.Parse(Console.ReadLine());

            Console.WriteLine(IsPrime(input));
        }
        private static bool IsPrime(long n)
        {
            if (n < 2)
            {
                return false;
            }
            for (int i = 2; i <= Math.Sqrt(n); i++)
            {
                if (n % i == 0)
                {
                    return false;
                }
            }
            return true;
        }
    }
}