数论基本性质证明（欧拉函数、莫比乌斯反演）
一年前学的数论、半年前补的证明，今日附一句歌词：
Lights will guide you home, and ignite your bones, and I will try to fix you.
一起送给OI~
一年前学的数论、半年前补的证明，今日附一句歌词：
Lights will guide you home, and ignite your bones, and I will try to fix you.
一起送给OI~