import Data.List

solve :: [[Int]] -> String
solve ps = if lined then "YES" else "NO"
  where
    (firstPointX:firstPointY:[]) = head ps
    lined = all (==firstPointX) (map (!!0) ps) || all (==firstPointY) (map (!!1) ps)

main = do
  t <- readLn :: IO Int
  c <- getContents
  let ps = map (\l-> map (read::String->Int) $ words l) $ take t $ lines c
  putStrLn $ solve ps