module Main where

type Input  = (Int, Int, [Int])
type Output = Int

parse :: String -> Input
parse s =
    let
        [n, x] =
            map read
            . words
            . head
            $ lines s

        ss =
            map read
            . words
            . (!! 1)
            $ lines s
    in
        (n, x, ss)

solve :: Input -> Output
solve (n, x, ss) =
    sum ss - pred n * x

render :: Output -> String
render =
    show

main :: IO ()
main =
    interact
        ( render
        . solve
        . parse
        )