Saitama Destroys Hotel

1) we will be create new array, lenght = max floor
2) we will add to index (if exist by number of floow) value of person time
3) read array from right to left 
4) in cicle (current index of cicle as "floow")
  4.1) if current vlue == 0, then incriminate result and continue
  4.2) if it is firs floow, maybe we need to wite, add current value and continue
  4.3) if curent value GREAT that result, then add value by formula (result = curent value - result)
  4.4) otherwise/else, just incriminate result

that it)

code:
  using System;
    public class Program
    {
        static void Main(string[] args)
        {
            string[] n_temp = Console.ReadLine().Split(' ');
            int n = Convert.ToInt32(n_temp[0]);
            int s = Convert.ToInt32(n_temp[1]);

            int[][] a = new int[n][];
            for (int a_i = 0; a_i < n; a_i++)
            {
                string[] a_temp = Console.ReadLine().Split(' ');
                a[a_i] = Array.ConvertAll(a_temp, Int32.Parse);
            }

            int[] workArray = new int[s + 1];

            Array.Sort(a, (ints, ints1) => ints[0].CompareTo(ints1[0]));
            for (int i = 0; i < a.Length; i++)
            {
                workArray[a[i][0]] = Math.Max(workArray[a[i][0]], a[i][1]);
            }

            // Console.WriteLine(Math.Max(s, a.Max(ints => ints[0] + ints[1]))); hack, but need more memmory

            int result = 0;

            for (int floow = workArray.Length -1; floow >= 0; floow--)
            {
                if (workArray[floow] == 0)
                {
                    result++;
                    continue;
                }

                if (floow == s)
                {
                    result += workArray[floow];
                }
                else if (workArray[floow] > result)
                {
                    result += workArray[floow] - result;
                }
                else if (workArray[floow] == floow)
                {
                    continue;
                }
                else
                {
                    result++;
                }
            }

            Console.WriteLine(result);
        }
    }