Finding Total Capacitance

I need help finding the total capacitance of this circuit.
Need to know how to solve it, not just the answer.

https://lh5.googleusercontent.com/-6hcYq_sYWCg/UUu7UncTJKI/AAAAAAAADCE/GJ30-tlh2Hw/s629/6.54.jpg

The diagram can be redrawn to show more clearly the layout of the various capacitors.

http://s1167.photobucket.com/user/allanw…

This makes it easier to work out the various parallel & series combinations.

group them and simplify:

step1- lower side: (3µ parallel 4µ=7µ) series 6µ means 6*7/13
step2- upper side: 12 series (3µ parallel 3µ=6µ) means 12*6/18
step2- lower side (result step1) parallel to upper side (result step2)means result step1*step2/(step1+step2)