Prime Numbers

using System;

namespace prime
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            int a;
            int n;
            int.TryParse(Console.ReadLine(), out n);
            Console.WriteLine ("The prime numbers in the range from 0 to " + n + " are: ");
            for (a = 2; a <= n; a++)
            {
                bool res1 = ((a % 2) == 0);
                bool res2 = ((a % 3) == 0);
                bool res3 = ((a % 5) == 0);
                bool res4 = ((a % 7) == 0);
                if (!res1 && !res2 && !res3 && !res4)
                {
                    Console.WriteLine (a);
                }
            }
        }
    }
}