????????????520 ????????? ??????520????????

?????????520?????????

???????????????????????????????β???????1???????Σ?????????????????????η??!~

?????10??????????12????????1???????Σ???ο??????2??10???????20????仨??????15?????????

????????????????????????20*15=300?????????????????????3???????????????20????????????60?Σ?????????????

???12?????????8?????10????????? 8*10=80

????????????????????????????????