Location Detection

Implement a prototype service to detect a user's location based on their IP addresses.

The IP addresses belonging to the IPv$4$ space are conventionally represented by four octets, $"$a$.$b$.$c$.$d$"-$ such as $127\mathrm{.}10\mathrm{.}20\mathrm{.}30.$ To keep it simple, these IP addresses are classified into $5$ different regions indexed from $1$ to $5$ on the basis of the order of the bits in the first octet.