diff --git a/src/main/java/me/hatter/math/ModularInv.java b/src/main/java/me/hatter/math/ModularInv.java
index 641e383..03381b9 100644
--- a/src/main/java/me/hatter/math/ModularInv.java
+++ b/src/main/java/me/hatter/math/ModularInv.java
@@ -28,6 +28,7 @@ public class ModularInv {
     }
 
     // https://zhuanlan.zhihu.com/p/426499159
+    // 扩展欧几里得算法
     // def modular_inv(a, p):
     //    x, y, m = 1, 0, p
     //    while a > 1: