Count number of unique words in a string in excel

I have an excel column like

column1
AA,BB,AA,BB,CC
DD,DD,EE
AA,AA
WW,EE,QQ,QQ

I want to count number of unique words in each cell and get an output like as follows

column1             column2
AA,BB,AA,BB,CC      3   
DD,DD,EE            2
AA,AA               1
WW,EE,QQ,QQ         3

How do i do this?