2zadacha5variant

            int sumsIndex = 0;// se vurti v cikula sus vseki 2 dvoiki 4isla primer 1 2 3 4 5 6 imaem 3 sumsIndex
            // vuv for cikala e +=2 zashtoto zimame 2 po 2 4islata i gi subirame naprime 1 2 3 4 5 6 / sumsIndex e 3 7 11

            // zapochavame ot nums.Length - 1 za da mi zima 2 po  2 4islata
            for (int i = 0; i < nums.Length - 1; i += 3)
            {
                sums[sumsIndex] = int.Parse(nums[i]) + int.Parse(nums[i + 1] + int.Parse(nums[i + 2]));

               // sums[sumsIndex] = sums[sumsIndex] / 4;

                sumsIndex++;
            }
            // for cikala koito mi sravnqva vsqka sus vsqka dvoika i zatova go vurti na 1 a ne na 2 kakto purviqt
            int diff = 0;
            for (int j = 0; j < sums.Length - 1; j++)
            {
             if (Math.Abs(sums[j] - sums[j + 1]) > diff)
                {
                   diff = Math.Abs(sums[j] - sums[j + 1]);
                }
             }
            // output
            if (diff == 0)
            {
                Console.WriteLine("Yes, value=" + sums[0]);
            }
            else
            {
                Console.WriteLine("No, maxdiff=" + diff);
            }

            }
        }
    }