using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        Regex regex = new Regex("...");

        var matches = regex.Matches("abcdefghijklmnop");

        Console.WriteLine(matches.Count);

        foreach (var match in matches)

        {

            Console.WriteLine(match);

        }

    }

}