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));
}
}
dXNpbmcgU3lzdGVtOwp1c2luZyBTeXN0ZW0uVGV4dC5SZWd1bGFyRXhwcmVzc2lvbnM7CnVzaW5nIFN5c3RlbS5MaW5xOwp1c2luZyBTeXN0ZW0uSU87CnB1YmxpYyBjbGFzcyBUZXN0CnsKCXB1YmxpYyBzdGF0aWMgdm9pZCBNYWluKCkKCXsKCQl2YXIgZGF0YSA9ICIyMzQ1Njc4OTAxIjsKCQl2YXIgcmVzID0gUmVnZXguTWF0Y2hlcyhkYXRhLCBAIig/PShcZHs0fSkpIikKCQkJCQkuQ2FzdDxNYXRjaD4oKQoJCQkJCS5TZWxlY3QocCA9PiBwLkdyb3Vwc1sxXS5WYWx1ZSkKCQkJCQkuVG9MaXN0KCk7CgkJQ29uc29sZS5Xcml0ZUxpbmUoc3RyaW5nLkpvaW4oIlxuIiwgcmVzKSk7Cgl9Cn0=