import Control.Monad
import Data.Char

main :: IO ()
main = do
  t <- readLn
  replicateM_ t $ do
    xs <- getLine
    print $ head $ last $ takeWhile (not . null) $ iterate step (map digitToInt xs)

step :: [Int] -> [Int]
step xs = zipWith add xs (tail xs)
  where
    add a b
      | s >= 10   = s`div`10+s`mod`10
      | otherwise = s
      where
        s = a+b