diff --git a/elegantbook.cls b/elegantbook.cls
index ccd3b8d..9a1cd64 100644
--- a/elegantbook.cls
+++ b/elegantbook.cls
@@ -80,6 +80,7 @@
 
 \RequirePackage{newtxtext}
 \RequirePackage{newtxmath}
+% \RequirePackage{mtpro2}
 %
 
 % font setting for text and math
@@ -99,10 +100,11 @@
 % \DeclareMathSymbol{\int}{\mathop}{CMlargesymbols}{"5A}%
 
 \let\intop\relax\let\sumop\relax\let\ointop\relax\let\prodop\relax
+
 \DeclareMathSymbol{\sumop}{\mathop}{CMlargesymbols}{"50}
 \DeclareMathSymbol{\intop}{\mathop}{CMlargesymbols}{"52}
-\DeclareMathSymbol{\ointop}{\mathop}{CMlargesymbols}{"49}
-\DeclareMathSymbol{\prodop}{\mathop}{CMlargesymbols}{"59}
+\DeclareMathSymbol{\ointop}{\mathop}{CMlargesymbols}{"48}
+\DeclareMathSymbol{\prodop}{\mathop}{CMlargesymbols}{"51}
 
 % \let\partial\relax
 % \DeclareMathSymbol{\partial}{\mathord}{CMletters}{"40}%