diff --git a/exam/ex.tex b/exam/ex.tex
index d49900e..997ee10 100644
--- a/exam/ex.tex
+++ b/exam/ex.tex
@@ -155,7 +155,8 @@
   \item \textbf{(16 points)} 
   \begin{enumerate}
 
-    \item \TODO
+    \item The chaining value size is $\unit[101]{bits}$ ($=g$) and the message
+      block size is $655-101=\unit[554]{bits}$.
 
     \item \TODO