fix toc depth

diff --git a/docs/math/mobius.md b/docs/math/mobius.md
index c657afa..c64ee33 100644 (file)
--- a/docs/math/mobius.md
+++ b/docs/math/mobius.md
@@ -684,7 +684,7 @@ signed main(){
 }
 ```
 
-# [Luogu P3768] 简单的数学题
+### [Luogu P3768] 简单的数学题
 
 求