using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        // Given a string s containing just the characters '[' and ']', determine if the input string is valid.

        // An input string is valid if each opening symbol has a corresponding closing symbol and the pairs of parentheses are properly nested.

​

        // Valid:

        // [[][][][]]

        // [[[[]]]]

        // [[][[[]][]]]

​

        // Not valid:

        // [[[[[[[]]

        // []]]

        // [[][][[]

​

        Console.WriteLine("Hello World");

    }

}