09. Pokemon Don't Go,C# Fundamentals

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp9
{
    class Program
    {
        static void Main(string[] args)
        {

            List<int> list = Console.ReadLine().Split().Select(int.Parse).ToList();
                List<int> DeletedNumbers = new List<int>();
            while (list.Count!=0)
            {
            bool check = true;
                int index = int.Parse(Console.ReadLine());
                int NumberIndex =0;


                    if (index<0)
                    {
                    //DeletedNumbers.Add(list[0]);
                        list.RemoveAt(0);
                        list.Insert(0,list[list.Count - 1]);
                    }
                    else if (index>list.Count-1)
                    {
                    //DeletedNumbers.Add(list[list.Count - 1]);
                        list.RemoveAt(list.Count - 1);
                        list.Add(list[0]);
                    }
                if (index > list.Count-1)
                {
                    NumberIndex = list[list.Count - 1];
                    index =list.Count - 1;
                    check = false;
                }
                else if (index<0)
                {
                    NumberIndex = list[0];
                    index = 0;
                    check = false;
                }
                else
                {

                    NumberIndex = list[index];
                }
                for (int i = 0; i < list.Count; i++)
                {
                    if (list[i]<=NumberIndex)
                    {
                    list[i] += NumberIndex;
                    }
                    else if (list[i]>NumberIndex)
                    {
                        list[i] -= NumberIndex;
                    }
                }
                DeletedNumbers.Add(NumberIndex);
                if (check==true)
                {
                    list.RemoveAt(index);
                }
            }
            double sum = DeletedNumbers.Sum();
            Console.WriteLine(sum);

        }
    }
}