using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		var str = "testteststete(segment1)tete(segment2)sttes323testte(segment3)eteste";
		var rx = @"\([^)]*\)";
    	var matches = Regex.Matches(str, rx).Cast<Match>().Select(p => p.Value).ToList();
    	var result = matches != null && matches.Count > 1 ? matches[1] : string.Empty;
        Console.WriteLine(result);
	}
}

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