I have a circuit diagram of 5 switches.

Reliability of switch A and B are 99.5%

while C,D and E are 98%.

Attachment 27614
What is the reliability of the circuit working?

I understand how to do a straight circuit multiplying the percents such as A and B being .995 * .995= .99025 or 99.025% but seeing how this circuit spreads out I am having a hard time finding the equations I must do and put together in order to find the percent if reliability. I do understand with all these switches the percent of reliability must be extremely high and close to 100%.

Anything will help at this point. Thanks!