A supercomputer requires subsystem $$A$$ and either subsystem $$B$$ or subsystem $$C$$ to function so as to save some critical data following a sudden loss of power to the computer. Subsystems A$,$ B$,$ and C are configured as shown below.

Use the following component reliability values to determine the probability that critical data will not be saved following a loss of power: Ra $=0\mathrm{.}99,$ Rb $=0\mathrm{.}98,$ Rc $=0\mathrm{.}999,$ Rd $=0\mathrm{.}998,$ and Re $=0\mathrm{.}99.$