diff --git a/src/java/simpledb/optimizer/JoinOptimizer.java b/src/java/simpledb/optimizer/JoinOptimizer.java
index 3d8d7b9b..ec93ea84 100644
--- a/src/java/simpledb/optimizer/JoinOptimizer.java
+++ b/src/java/simpledb/optimizer/JoinOptimizer.java
@@ -199,7 +199,7 @@ public <T> Set<Set<T>> enumerateSubsets(List<T> v, int size) {
 
     /**
      * Compute a logical, reasonably efficient join on the specified tables. See
-     * PS4 for hints on how this should be implemented.
+     * PS3 for hints on how this should be implemented.
      * 
      * @param stats
      *            Statistics for each table involved in the join, referenced by
@@ -221,7 +221,7 @@ public List<LogicalJoinNode> orderJoins(
             Map<String, TableStats> stats,
             Map<String, Double> filterSelectivities, boolean explain)
             throws ParsingException {
-        //Not necessary for labs 1--3
+        // Not necessary for labs 1--2
 
         // See the Lab 3 writeup for some hints as to how this function
         // should work.