02_Numbers1toNDivisible

using System;

/*
 * 2. Write a program that prints all the numbers from 1 to N,
 * that are not divisible by 3 and 7 at the same time.
 */
class Numbers1toNDivisible
{
    static void Main()
    {
        int n;

        Console.Write("Please enter N: ");
        string str = Console.ReadLine();

        if (!int.TryParse(str, out n))
        {
            Console.WriteLine("Invalid number: {0}", str);
        }
        else
        {
            for (int i = 1; i <= n; i++)
            {
                if (i % (3 * 7) != 0)
                {
                    Console.WriteLine(i);
                }
            }
        }
    }
}