using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
		var pattern = @"^[^_]*_[^_]*(?:_([^_]+))+";
        var str = "ABC_BC_BE08_C1000004_0124";
        var strings = Regex.Match(str, pattern).Groups[1].Captures.Select(c => c.Value);
        
        foreach (String s in strings)
        {
            Console.WriteLine(s);
        }
	}
}