using System;
using System.IO;
using System.Text.RegularExpressions;
public class Test
{
	public static void Main()
	{
		String s = ">>>tagA\ncontents 1\n<<<tagA\n...\n>>>tagB\ncontents 2\n<<<tagB\n...";
        var matches = Regex.Matches(s, @">>>(?<tagName>.+?)[\r\n]+(?s:(?<contents>.*?))<<<");
        foreach (Match m in matches) {
            Console.WriteLine(m.Groups["tagName"].Value);
            Console.WriteLine(m.Groups["contents"].Value);
        }
	}
}
 
 

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