When robots come off the factory floor, they have no name.

The first time you boot them up, a random name is generated in the format
of two uppercase letters followed by three digits, such as RX837 or BC811.

Every once in a while we need to reset a robot to its factory settings,
which means that their name gets wiped. The next time you ask, it will
respond with a new random name.

The names must be random: they should not follow a predictable sequence.
Random names means a risk of collisions. Your solution should ensure that
every existing robot has a unique name.

When robots come off the factory floor, they have no name.

The first time you boot them up, a random name is generated in the format
of two uppercase letters followed by three digits, such as RX837 or BC811.

Every once in a while we need to reset a robot to its factory settings,
which means that their name gets wiped. The next time you ask, it will
respond with a new random name.

The names must be random: they should not follow a predictable sequence.
Random names means a risk of collisions. Your solution must ensure that
every existing robot has a unique name.

Use 'must' rather than 'should'
Use 'must' rather than 'should'
