using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

​

    private static void Rotate(int[][] matrix, int n)

    {

        for (var layer = 0; layer < n / 2; ++layer)

        {

            var first = layer;

            var last = n - 1 - layer;

            for (var i = first; i < last; ++i)

            {

                var offset = i - first;

                var top = matrix[first][i]; // save top

                // left -> top

                matrix[first][i] = matrix[last - offset][first];

                // bottom -> left

                matrix[last - offset][first] = matrix[last][last - offset];

                // right -> bottom

                matrix[last][last - offset] = matrix[i][last];

                // top -> right

                matrix[i][last] = top; // right <- saved top

            }

        }

    }

}