import Data.Char
import Control.Monad
import Data.Maybe
import qualified Data.ByteString.Char8 as BS

readInt = fst . fromJust . BS.readInt
getInt = readInt <$> BS.getLine

main = do
    n <- getInt
    s <- getLine
    putStrLn $ map (rot n) s

rot n c = chr $ ord 'A' + ((ord c) - ord 'A' + n) `mod` 26