?? ????15?????????? ????50???
????:1????????:??498??????
2???????
3?????95?????
4??????????
5??????
??????????6???21?? ?(ABC)??????,????20??,???????????????,??????19????????????????????????????,????15??
?????:????????????(ABC)?????????,??,??????????,??
??????????,????,????????????????????????????,????20?????????30??????????,???50?????????????
????,????????
???,?????????????,????????
???????????????:?????????