module Main where

import Data.Foldable (Foldable (toList))
import Data.Sequence (Seq, fromList, index, splitAt, (<|), (|>))
import qualified Data.Sequence  as Seq

cxor :: Char -> Char -> Char
cxor '0' '0' = '0'
cxor '1' '1' = '0'
cxor _ _ = '1'

solve2 :: Int -> Int -> String -> String
solve2 n k e = go e solseq bsum
  where
    k' = k - 1
    solseq = fromList $ replicate k' '0'
    bsum = '0'
    go :: String -> Seq Char -> Char -> String
    go "" acc _ = drop k' $ reverse $ drop k' $ toList acc
    go (x : xs) acc bsum =
        let newC = x `cxor` bsum
            acc' = (newC <| acc)
            bsum' = newC `cxor` bsum `cxor` index acc' k'
         in go xs acc' bsum'

main :: IO ()
main = do
    [n, k] <- map read . words <$> getLine
    e <- getLine
    putStrLn $ solve2 n k e
    putStrLn ""