using System;
using System.IO;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
		var s = "Line1\rLine2\r\nLine3";
        var res = Regex.Replace(s, "\r(?!\n)", "\r\n");
        Console.WriteLine(res.Replace("\r","CR").Replace("\n","LF\n"));
	}
}