import Control.Applicative ((<$>))
import Data.Char (ord, chr)

main :: IO ()
main = do
  solve <$> getLine >>= putStrLn

solve :: String -> String
solve s = map decrypt $ zip [1..] s

decrypt :: (Int, Char) -> Char
decrypt (d, c) = chr $ (ord c - ord 'A' - d) `mod` 26 + ord 'A'