FoldAndSum

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

public class AppendLists
{
    public static void Main()
    {
        var nums = Console.ReadLine().Split().Select(int.Parse).ToArray();

        int[] firstHalf = new int[nums.Length / 2];
        int[] secondHalf = new int[nums.Length / 2];
        int[] firstSum = new int[nums.Length / 2];
        int[] secondSum = new int[nums.Length / 2];

        for (int i = 0; i < nums.Length / 2; i++)
        {
            firstHalf[i] = nums[i];
        }
        for (int i = 0; i < nums.Length / 2; i++)
        {
            secondHalf[i] = nums[nums.Length / 2 + i];
        }
        for (int i = 0; i < firstHalf.Length / 2; i++)
        {
            firstSum[i] = firstHalf[i] + firstHalf[firstHalf.Length - 1 - i];
            secondSum[i] = secondHalf[i] + secondHalf[firstHalf.Length - 1 - i];
        }

        int index = 0;
        for (int i = firstSum.Length / 2; i < firstSum.Length; i++)
        {
            firstSum[i] = secondSum[index];
            index++;
        }

        Console.WriteLine(string.Join(" ", firstSum));

    }
}