using System;

​

public class Program

{

    public static void Main()

    {

        int size = 15;

        for (int i = 0; i < size; i++)

        {

            for (int j = 0; j < size; j++)

            {

                if (i <= j)

                {

                    Console.Write("x");

                }

                else

                {

                    Console.Write(" ");

                }

            }

                Console.WriteLine(" ");

        }

​

    }

}