module Main where

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

main :: IO ()
main = do
  [n, k] <- map (fst . fromJust . BS.readInt) . BS.words <$> BS.getLine
  an     <-
    sortOn Down . map (fst . fromJust . BS.readInt) . BS.words <$> BS.getLine
  let r = maximum $ [ sum $ take i an | i <- [1 .. k] ]
  print r