(use '[clojure.string :only (split triml)])

(defn read-pair []
  (mapv #(Long/parseLong %) (split (read-line) #" ")))

(
        let [
          n_t (read-line) 
          n (Integer/parseInt n_t)
          [Xs Ys]  (loop [N n xs '() ys '()]
          (if (pos? N)
          (let [[x y] (read-pair)]
            (recur (dec N) (cons x xs) (cons y ys))
          )
          [xs ys]))
        
        ]
        
        (println (if (or (apply = Xs) (apply = Ys)) "YES" "NO"))

)