diff --git a/chapter2/recommendations.py b/chapter2/recommendations.py
index c3f0089..976a7b5 100644
--- a/chapter2/recommendations.py
+++ b/chapter2/recommendations.py
@@ -35,7 +35,7 @@ def sim_distance(prefs,person1,person2):
   sum_of_squares=sum([pow(prefs[person1][item]-prefs[person2][item],2) 
                       for item in prefs[person1] if item in prefs[person2]])
 
-  return 1/(1+sum_of_squares)
+  return 1/(1+sqrt(sum_of_squares))
 
 # Returns the Pearson correlation coefficient for p1 and p2
 def sim_pearson(prefs,p1,p2):