solve :: Int -> Int -> IO ()
solve c n  = do
  if n < c then return ()
  else do
    v1 <- readLn :: IO Integer
    v2 <- readLn :: IO Integer
    if (v1+v2) >= 10^80 then putStrLn "overflow"
    else print (v1+v2)
    solve (c+1) n

main :: IO ()
main = do
  n <- readLn :: IO Int
  solve 1 n