class Time3(h:Int, m:Int){
  require(h > 0 && h < 24 && m > 0 && m < 59)
  private var t = h * 60 + m

  def hour:Int = t / 60
  def hour_=(h:Int) {
    require(h > 0 && h < 24)
    t = t % 60 + h * 60
  }

  def minute:Int = t % 60
  def minute_=(m:Int) {
    require(m > 0 && m < 59)
    t = t / 60 * 60 + m
  }

  def before(other:Time3):Boolean =
    other.t > t
}