using System;

public class Program

{

    public static void Main()

    {

        decimal _decimal;

        _decimal = decimal.Parse("-1234567.9999999");

        Console.WriteLine(_decimal); // -1234567.9999999

        Console.WriteLine(Math.Floor(_decimal)); // -1234568 (bad)

        Console.WriteLine(Math.Truncate(_decimal)); // -1234567 (correct)

        Console.WriteLine(Math.Floor(Math.Abs(_decimal))); // 1234567 (correct but positive)

        Console.WriteLine(Math.Abs(Math.Floor(_decimal))); // 1234568 (bad)

        Console.WriteLine((_decimal > 0 ? 1 : -1) * Math.Floor(Math.Abs(_decimal))); // 1234567 (correct)

    }

}