using System;
using System.Text.RegularExpressions;
using System.Linq;
using System.IO;
public class Test
{
	public static void Main()
	{
		var data = "2345678901";
		var res = Regex.Matches(data, @"(?=(\d{4}))")
					.Cast<Match>()
					.Select(p => p.Groups[1].Value)
					.ToList();
		Console.WriteLine(string.Join("\n", res));
	}
}