import Control.Applicative
import Control.Monad
import Data.List
import Data.Maybe

paren :: ([Int], [(Int, Int)]) -> (Char, Int) -> ([Int], [(Int, Int)])
paren (s : ss, res) (x, i)
    | x == '('  = (i : s : ss, res)
    | otherwise = (ss, (s, i) : res)

solve :: Int -> Int -> String -> Int
solve n k s = 
    if a == k then b else a
    where 
        (a, b) = fromJust . find (\ (a, b) -> a == k || b == k) . snd . foldl' paren ([-1], []) $ zip s [1 .. n]

main = do
    [n, k] <- map read . words <$> getLine :: IO [Int]
    s <- getLine
    print $ solve n k s