public class GcdCalculator1
{

	public static int Gcd (int p, int q)
	{
		int r;
		p = System.Math.Abs(p);
		q = System.Math.Abs(q);
		while (q > 0)
		{
			r = p % q;
			p = q;
			q = r;
		}
		return p;
	}

	protected const string Hint =
		"Please call the gcd calculator with two integer arguments!";
		
	public static void Main (string[] args)
	{
		if (args.Length < 2)
		{
			System.Console.WriteLine("Missing Argument. " + Hint);
		} 
		else 
		{
			try 
			{
				System.Console.WriteLine
					(Gcd
						(System.Convert.ToInt32(args[0]),
						 System.Convert.ToInt32(args[1])));
			} 
			catch (System.Exception e) 
			{
					System.Console.WriteLine("Wrong Argument. " + Hint);
			}
		}
	}
}