Is my entropy calculation correct? Clustering entropy example

Question

I would like to calculate entropy of this example scheme

http://nlp.stanford.edu/IR-book/html/htmledition/evaluation-of-clustering-1.html

Equation of entropy

Then the entropy is (the first line)

So entropy is for this scheme

For the first cluster - ( (5/6)*Log(5/6) + (1/6)*Log(1/6) ) 
For the second cluster  - ( (1/6)*Log(1/6) + (1/6)*Log(1/6) + (4/6)*Log(4/6) )
For the third cluster  - ( (2/5)*Log(2/5) + (3/5)*Log(3/5) )

Final entropy is :

 FirtCluster_Entropy + SecondCluster_Entropy  + ThirdCluster_Entropy  

Am i correct?