Write a program sum of the all numbers from 0 to which is given specific the number in C#

class SumNumber

    {

        static void Main()

        {

            int n = 0;

            Console.WriteLine("Enter the number");

            Console.Write("The Num = ");

            n = int.Parse(Console.ReadLine());

            int num = 1;

            int sum = 1;

            Console.Write("The sume is :  1");

            while (num < n)

            {

                num++;

                sum += num;

                Console.Write("+" + num);

            }

            Console.WriteLine(" = " + sum);

            Console.ReadLine();

        }

    }

Output: