import Data.List
import Control.Monad

main = do
  [n,m,a] <- getList
  when (n/=0) $ do
    prm <- replicateM m getList
    print $ solve (sort prm) a
    main
  where getList = getLine >>= return . map read . words

solve = foldr (\[_,p,q] -> (swap p q .)) id
swap a b n = if a==n then b else if b==n then a else n