Story

[rabestro]

Given a simple text file with IPv4 addresses. One line - one address, like this:

145.67.23.4
8.34.5.23
89.54.3.124
89.54.3.124
3.45.71.5
...
The file size is not limited and can take tens and hundreds of gigabytes.

Your task is to count the number of unique addresses in this file, spending as little memory and time as possible.