Scanf.sscanf (read_line ()) "%d %d" (fun n avr ->
               let line2 = read_line () in
               let numbers = List.map (fun s -> int_of_string s)
                                      (Str.split (Str.regexp " ") line2)(* (String.split_on_char ' ' line2) *)
               in
               if (n * avr) = (List.fold_left (+) 0 numbers) then
                 Printf.printf "YES\n"
               else
                 Printf.printf "NO\n"
             );;