When I/O is slow the first thing to check is to make sure it is buffered. This is true in every language and library. Just turns out this guy ran into something

When I/O is slow the first thing to check is to make sure it is buffered. This is true in every language and library. Just turns out this guy ran into something with a default that matches the "read input from terminal" case instead of the "process millions of lines" case.