[SDOI2017]Êý×Ö±í¸ñ

Description: Çó $ \prod_{i=1}^n \prod_{j=1}^m f[gcd(i,j)]$ ÆäÖÐ $f?$ a56爆大奖在线娱乐ì³²¨ÄÇÆõÊýÁÐ Ê×ÏÈÏÔÈ»£º $ Ans = \prod_{d=1}^{min(n,m)} \prod_{i=1}^{ \lfloor \frac{n}{d} \rfl