import scala.collection.mutable.ArrayBuffer
object Main {
  def main(args: Array[String]): Unit = {
    val sc = new java.util.Scanner(System.in)
    val n = sc.nextInt()
    val inputRobots: ArrayBuffer[Robot] = ArrayBuffer()

    1.to(n).foreach { _ =>
      val position = sc.nextInt()
      val armLength = sc.nextInt()
      inputRobots += new Robot(position, armLength)
    }

    var robots = inputRobots.sortBy(_.position)
    var answer: Int = 0

    while (robots.nonEmpty) {
      answer += 1
      val robot = robots.head
      robots = robots.filter(_.armStart > robot.armEnd)
    }

    println(answer)
  }
}

class Robot(val position: Int, val armLength: Int) {
  def armStart: Int = position - armLength + 1
  def armEnd: Int = position + armLength - 1
}
