????????????0。01%?ˉ?99。99%????????????è???????????????±±?¤§???
??o?o????????o??????μ??3?????′????′2???é?￠?-?????￥1????????????é?????????oo?????-?????1???è?-??????
????o??????????è????￥?o?????????????
?ˉ???o?ˉ?èμ?é??????o??????′??-???a?????????-?a???????′??-é?′é???oo?????o??￡???
???????ooé???-????????????????é|?????o???????
é????o??1é?????????????????????????¨èμ·??￥???è???????????????????o?????????é????o?o?è??è??????±???·?±????
??ˉ?-???°?????¨????o?????-￠?????????é?￡??????????????????è????????é???o?????o??2???￡???
??ˉa?????????ˉ?é??a?????
??¤??a??′??-é?′????1??????1?1????é?′?2?è??èμ·??￥???
???§?§????è???1?????°±è|??ˉ1??3?o???????è???????a??ˉ????????o??????
?è??????????±??????é?￠?????3èμ???????è????ˉ?￥?????????????
??°?é±?????21??????????????????è???oˉ??o?o???????èμ￠????|??|???±?????????
????é?¨??2?????????è??è?????????¤a??￡????o???????
?è????o???é￡????è???2????????????????è§???????è???o?a?|a?|???
è???????????????????1?1?????????§?1????èˉ′è?????è???????????????§??°±??′??￥????????1?????-?????1??2???
??????????????¤????°±??ˉ??-?????1????????°??°??1?????-?????1?°±è??è?·è?????
è????????èμ°???èμ°????????′???????????°???a?????????ˉ?é??a???????°???????????ˉè?a?·±??????è??è????????