import Control.Applicative ((<$>))
import Data.List (foldl')

swap :: Int -> [Int] -> Int
swap n (p : q : _)
    | n == p    = q
    | n == q    = p
    | otherwise = n

main :: IO ()
main = do
    n <- readLn
    _ <- getLine
    print . foldl' swap n . map (map read) . map words . lines =<< getContents