overflow x y
  | 10^80 > (read x + read y) = show (read x + read y)
  | otherwise = "overflow"

oF xs'@(x:y:xs)
  | xs' == [] = []
  | otherwise  = (overflow x y) : oF xs

main = do
  s' <- getContents
  let s = tail $ lines s'
  mapM_ putStr $ oF s