数论套题

组合数取模：http://cache.baiducontent.com/c?m=9f65cb4a8c8507ed4fece7631046893b4c4380146d96864968d4e414c42246000239e9b927230d57938327365ff8540abdb6652969423db39cc88f41d7b9866d72c8713b676a835665d80edfb85154b537912afede6af0ce862592dec5a2d54320c944040a97818d4d7315&p=882a9546d7970eb44ba9cc2d0214c6&newp=8565c64ad4934eaf5becc5645a4188231610db2151d0d1&user=baidu&fm=sc&query=%D7%E9%BA%CF%CA%FD%C8%A1%C4%A3&qid=c526957f000223ac&p1=3

还是逆元好用。。。