diff --git a/Concurrent Systems/notes/13 - Weak Bisimilarity.md b/Concurrent Systems/notes/13 - Weak Bisimilarity.md
index 7a51762..8489dea 100644
--- a/Concurrent Systems/notes/13 - Weak Bisimilarity.md	
+++ b/Concurrent Systems/notes/13 - Weak Bisimilarity.md	
@@ -93,4 +93,5 @@ This is a family of relations:
 
 Furthermore, we should also consider commutativity of parallel in pairs of the second, third, fourth, sixth, seventh and eighth form.
 
-Thus, R is actually made up of 1+6+2+2+9+6+6+2=34 pairs.
+Thus, R is actually made up of 1+6+2+2+9+6+6+2 = 34 pairs.
+ *exercise: write down the LTSs*