using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		var strs = new[] { "aaa bbbb; Name=John Lewis; ccc ddd; Age=20;", "AAA bbbb; Age=21;" };
    	var pattern = @"(?:\bName=(?<Name>[^;]+).*?;\s+)?\bAge=(?<Age>\d+)";
    	foreach (var str in strs) 
    	{
    		var result = Regex.Match(str, pattern);
    		if (result.Success) 
      			Console.WriteLine("Name: \"{0}\", Age: \"{1}\"", result.Groups["Name"].Value, result.Groups["Age"].Value);
    	}
	}
}

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