private static int isKingKong(ArrayList<Card> list) {
		assert(list.size() == EFFECTIVE_CARD_NUM);
		
		int change = 0;
		int changePos = 0;
		
		for ( int i = 1; i < 5; i++ ){
			if (list.get(i).getPoint() != list.get(i - 1).getPoint()){
				change++;
				changePos = i;
				if ( change > 1 || (changePos != 1 && changePos != 4) ){
					return -1;
				}
			}
		}
		
		return list.get(changePos - 1).getPoint();
	}