using System;

public class Program

{

    public static void Main()

    {

        int sum = 0;

        Console.WriteLine("Press 0: find summation of even number");

        Console.WriteLine("Press 1: find summation of odd  number");

        Console.Write("Input your option: ");

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

        Console.WriteLine();

        if(num == 0)

        {

           for (int i = 1; i <=100; i++)

                {

                    if (i%2 == 0)

                    {

                      sum = sum + i;

                          if ( sum == 2550)

                          {

                            Console.WriteLine("Summation of even is {0:n0}",sum);

                          }  

                    }

               }

        }

        else if (num == 1)

        {

           for (int i = 1; i <=100; i++)

                {

                    if ( i%2 != 0)

                    {

                      sum = sum + i;

                          if ( sum == 2500)

                          {

                            Console.WriteLine("Summation of odd is {0:n0}",sum);

                          }  

                    }

               }

        }

        else

        Console.WriteLine("You input wrong number!");

    }

}