using System.IO;

​

namespace ConsoleApp1

{

    class Program

    {

        static void Main(string[] args)

        {

            string pthIn = @"C:\Users\Липа Филимонов\Desktop\aplusb.in";

            string pthOut = @"C:\Users\Липа Филимонов\Desktop\aplusb.out";

​

            int sum; 

            string str;

            StreamReader fin = new StreamReader(pthIn);

            str = fin.ReadToEnd();

            fin.Close();

            string[] arr = str.Split(' ');

            sum = int.Parse(arr[1]) + int.Parse(arr[0]);

            StreamWriter fout = new StreamWriter(pthOut);

            fout.Write(sum);

            fout.Close();                     

        }

    }

}

​