using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		var s = "test.BO.ID";
    	var result = Regex.Match(s, @"(?<=\.).*");
    	if (result.Success)
        	Console.WriteLine(result.Value);
        var result2 = Regex.Match(s, @"\.(.*)");
    	if (result2.Success)
        	Console.WriteLine(result2.Groups[1].Value);
	}
}

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