import scala.io.Source.stdin

object Main extends App {
  stdin.getLines.foreach { s =>
    val n = s.split(" ").map(_.toDouble)
    val a = n(2)-n(0);val b = n(3)-n(1);val c = n(6)-n(4);val d = n(7)-n(5)
    if( Math.abs((a*c)+(b*d)) < 0.0000000001) println("YES") else println("NO")
  }
}