diff --git a/rules.tex b/rules.tex
index 6f9cc7a3e447191db8b5b686b642982e449762bb..19a665bf25b18fb34d34e13158e3064f89332f9e 100644
--- a/rules.tex
+++ b/rules.tex
@@ -1,4 +1,4 @@
-\documentclass[a5paper,openany]{book}
+\documentclass[a4paper,openany]{book}
 \usepackage{bind}
 
 \date{\today}