using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        Regex rx = new Regex("\\[[^\\]]*\\]", RegexOptions.Compiled | RegexOptions.IgnoreCase);

        Console.WriteLine(rx.Replace("\"M3[R0003]\": \"Y\", [FOO]", ""));

        Console.WriteLine("Hello World");

    }

}