import qualified Data.ByteString.Char8 as BC
import Data.Maybe (fromJust)
import Data.List
import Data.Array.IO
import Control.Monad

type Memo = IOUArray (Int, Int) Int

main = do
  n <- readLn :: IO Int
  edge <- (\[x,y,z] -> zip3 x y z) . transpose <$> replicateM (n-1) getIntListBC
  [q, k] <- map read . words <$> getLine :: IO [Int]
  query <- (\[x,y] -> zip x y) . transpose <$> getInt2DListBC
  adjacency <- newArray ((1, 1), (n, n)) (maxBound :: Int) :: IO Memo
  mark <- newArray (1, n) False :: IO (IOUArray Int Bool)
  weight <- newArray (1, n) 0 :: IO (IOUArray Int Int)
  neighbors <- newArray ((1, 0), (n, n-1)) 0 :: IO Memo
  foldM (initEdge neighbors) adjacency edge
  foldM memoize adjacency [1..n]
  kn <- readArray neighbors (k, 0)
  writeArray mark k True
  kNeighbors <- readNeighbors neighbors k kn
  print kNeighbors
  foldM (search adjacency weight neighbors k k) mark kNeighbors
  ans <- mapM (readWeight weight k) query
  print =<< getElems adjacency
  print =<< getElems neighbors
  print =<< getElems weight
  putStrLn . unlines . map show $ ans

bsToInt :: BC.ByteString -> Int
bsToInt = fst . fromJust . BC.readInt

getIntListBC :: IO [Int]
getIntListBC = map bsToInt . BC.words <$> BC.getLine

getInt2DListBC :: IO [[Int]]
getInt2DListBC = map (map bsToInt . BC.words) . BC.lines <$> BC.getContents

memoize :: Memo -> Int -> IO Memo
memoize memo i = do
  writeArray memo (i, i) 0
  return memo

initEdge :: Memo -> Memo -> (Int, Int, Int) -> IO Memo
initEdge neighbors memo (x, y, d) = do
  xn <- readArray neighbors (x, 0)
  yn <- readArray neighbors (y, 0)
  writeArray memo (x, y) d
  writeArray memo (y, x) d
  writeArray neighbors (x, 0) $ xn + 1
  writeArray neighbors (y, 0) $ yn + 1
  writeArray neighbors (x, (xn+1)) y
  writeArray neighbors (y, (yn+1)) x
  return memo

--始点k 前pre 現在i
search :: Memo -> IOUArray Int Int -> Memo -> Int -> Int -> IOUArray Int Bool -> Int -> IO (IOUArray Int Bool)
search edge weight neighbors k pre mark i = do
  isMark <- readArray mark i
  case isMark of
    True -> do
      return mark
    False -> do
      writeArray mark i True
      wI <- readArray edge (pre, i)
      wSum <- readArray weight pre
      writeArray weight i (wSum+wI)
      n <- readArray neighbors (i, 0)
      nI <- readNeighbors neighbors i n
      print nI
      return =<< foldM (search edge weight neighbors k i) mark nI

readNeighbors :: Memo -> Int -> Int -> IO [Int]
readNeighbors neighbors i n = mapM (\x -> readArray neighbors (i, x)) [1..n]

readWeight :: IOUArray Int Int -> Int -> (Int, Int) -> IO Int
readWeight weight k (x, y) = do
  kx <- readArray weight x
  ky <- readArray weight y
  return $ kx + ky