object Main extends App {
  val a: String = scala.io.StdIn.readLine()
  val b: String = scala.io.StdIn.readLine()

  val resolveNum = (n: String) =>
    if (n.matches("^(?!(00|0.+))[0-9]{1,5}") && n.toInt <= 12345) {
      Some(n.toInt)
    } else {
      None
  }

  val aIntOpt = resolveNum(a)

  val bIntOpt = resolveNum(b)

  val ans = for {
    a <- aIntOpt
    b <- bIntOpt
  } yield {
    a + b
  }

  println(if (ans.nonEmpty) "OK" else "NG")

}