为了应对附近敌对国家的威胁，某国R已经更新了他们的导弹防御系统。这种新型的防御系统能够击落一系列的导弹，只要这些导弹是按上升或下降的高度顺序袭击。-In response to the threat of hostile countries nearby, R has been updated a country of their missile defense system. The new defense system to shoot down a series of missiles, these missiles as long as the increase or decrease according to the height of the order of attack.