diff --git a/document_en/math.md b/document_en/math.md
index 6154802..baff60e 100644
--- a/document_en/math.md
+++ b/document_en/math.md
@@ -78,7 +78,7 @@ It returns the answer in $\bmod 2^{\mathrm{64}}$, if overflowed.
 
 **@{keyword.complexity}**
 
-- $O(\log{(m+a)})$
+- $O(\log m)$
 
 ## @{keyword.examples}
 
diff --git a/document_ja/math.md b/document_ja/math.md
index 7fa4caa..11c85fa 100644
--- a/document_ja/math.md
+++ b/document_ja/math.md
@@ -75,7 +75,7 @@ $$\sum_{i = 0}^{n - 1} \left\lfloor \frac{a \times i + b}{m} \right\rfloor$$
 
 **@{keyword.complexity}**
 
-- $O(\log{(m+a)})$
+- $O(\log m)$
 
 ## @{keyword.examples}