(defn parse-input [s]
  (mapv #(Integer/parseInt %) (clojure.string/split s #" ")))

(defn to-range [[x l]]
  [(+ x l) (- x l)])

(defn to-ranges [ coll ]
  (map #(to-range %) coll))

(def min-int (Math/pow -10 9))
(defn yyy [xls]
  (reduce (fn [[cur res-cnt :as res] [x1 x2 :as x]]
             (if (<= cur x2)
               [x1 (inc res-cnt)]
               res))
          [min-int 0]
          (sort (to-ranges xls))))

(def in-robos
  (for [x (range (Integer/parseInt (read-line)))]
    (parse-input (read-line))))

(println (-> in-robos
             (yyy)
             last))