###name
###descirption
###input
###output
###sample input
###sample output
###toturial
先来看一个简单的变形
$$
\begin{aligned}
&\sum_{i=1}^{n}gcd(x,i)\
=&\sum_{d|x}\sum_{i=1}^{n}[gcd(x,i)=d]\
=&\sum_{d|x}\sum_{i=1}^{\lfloor\frac{n}{d}\rfloor}[gcd(\frac{x}{d},i)=1]\
=&\sum_{d|x}\sum_{i=1}^{\lfloor\frac{n}{d}\rfloor}\sum_{y|\frac{x}{d},y|i}\mu(y)\
=&\sum_{y|x}\sum_{d|\frac{x}{y}}\sum_{y|i,i\leq\lfloor\frac{n}{d}\rfloor}\mu(y)\
=&\sum_{y|x}\sum_{d|\frac{x}{y}}\frac{\lfloor\frac{n}{d}\rfloor}{y}\mu(y)\
=&\sum{}\
\end{aligned}
$$
题目让我们求的东西是这个
$$
\begin{aligned}
\sum_{i=1}^{n}gcd(\lfloor\sqrt[3]{i}\rfloor,i)
\end{aligned}
$$
###code
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