open Big_int;;

let () =
  let n = read_int () in
  let rec read = function
      0 -> ()
     | i -> let first = read_line () |> String.trim and
                second = read_line () |> String.trim in
            let result =
              if String.length first > 80 || String.length second > 80 then
                "overflow"
              else
                let first_int = big_int_of_string first and
                    second_int = big_int_of_string second in
                let sum = add_big_int first_int second_int |> string_of_big_int in
                if String.length sum > 80 then "overflow" else sum
            in
            print_endline result; read (i-1)
  in read n;;