using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        string dataString = Regex.Replace("^([1-9]{2})$", "");

        var data = Convert.ToDateTime("16Mar2020(mon)");

        Console.Write("data " + data.Day + ", mes " + data.Month + ", year " + data.Year);

    }

}