--- a/hws/hw01.tex	Thu Sep 26 15:11:25 2013 +0100
+++ b/hws/hw01.tex	Thu Sep 26 15:17:38 2013 +0100
@@ -29,6 +29,9 @@
 \item Assume the concatenation operation of two strings is written as $s_1 @ s_2$. 
 Define the operation  of \emph{concatenating} two sets of strings.
 
+\item Assume a set $A$ contains 4 strings and a set $B$ 7 strings, how many strings
+are in $A @ B$?
+
 \item How is the power of a language defined? (Hint: There are two rules, one for $\_\!\_^0$ and
 one for $\_\!\_^{n+1}$.)