using System;

public class Program

{

    public static void Main()

    {

        int c,t,n=0;

        Console.WriteLine("Input starting number");

        c=Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("Input ending number");

        t=Convert.ToInt32(Console.ReadLine());

        {

            if (c<t)

            {

                if (c%2==0)

                {

                    c=c+1;

                }

                    while (c<=t)

                    {

                        n=n+c;

                        c=c+2;

                    }

                Console.WriteLine("Additon is");

                Console.WriteLine(n);

            }

                    else

                    {

                        if (c%2==0)

                        {

                            c=c-1;

                        }

                            while(c>=t)

                            {

                                n=n+c;

                                c=c-2;

                            }

                        Console.WriteLine("Addition is");

                            Console.WriteLine(n);

    }

        }

    }

}