BZOJ.2154.Crash的数字表格(莫比乌斯反演)
给定$n,m$，求$$\sum_{i=1}^n\sum_{j=1}^m\mathbb{lcm}(i,j)$$
$n,m\leq10^7$。
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很久以前的奇怪但现在依旧成立的签名
attack is our red sun $$\color{red}{\boxed{\color{red}{attack\ is\ our\ red\ sun}}}$$ ------------------------------------------------------------------------------------------------------------------------
很久以前的奇怪但现在依旧成立的签名
attack is our red sun $$\color{red}{\boxed{\color{red}{attack\ is\ our\ red\ sun}}}$$ ------------------------------------------------------------------------------------------------------------------------
