{-# LANGUAGE FlexibleContexts, OverloadedStrings #-}
import Control.Applicative
import Control.Monad
import qualified Data.ByteString.Char8 as B
import Data.Maybe (fromJust)
import Text.Printf
import Debug.Trace

solve (s:ss) (t:ts) n =
  if s /= t then
    print n >> B.putStrLn s >> B.putStrLn t
  else
    solve ss ts (n+1)

main = do
  [n] <- getInts
  s <- B.words <$> B.getLine
  t <- B.words <$> B.getLine
  solve s t 1

-- util
getInts :: IO [Int]
getInts = map (fst . fromJust . B.readInt) . B.words <$> B.getLine

substr :: Int -> Int -> B.ByteString -> B.ByteString
substr b l s = B.take l $ B.drop b s