import scala.math._
import scala.annotation._
import scala.collection._
import scala.collection.{mutable => mut}
import scala.util.control.Breaks.{breakable,break}

object Main {
  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)

    val n, k = sc.nextInt
    println(
      if(n >= 2 * k - 1) "YES" else "NO"
    )
  }
}