using System;
using System.Linq;
using System.Text.RegularExpressions;
public class Test
{
	public static void Main()
	{
		
		var str = "This is a really long test string is this is this is this is this is this is this is thisit is this this has to be way more than 85 characters ssssssssssss";
		Console.WriteLine(Regex.Replace(str, @"(?s).{0,85}", 
				m => m.Value.EndsWith("\n") ? m.Value + "\t" : m.Value + "\n\t"));
	}
}