using System;

using System.Linq;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var s = "0.23.10.30";

        Console.WriteLine(s);

        var s1 = s.Replace("0.", "Review ");

        Console.WriteLine(s1);

​

        var s2 = Regex.Replace(s, @"^0.", "Review ");

        Console.WriteLine(s2);

    }

}