--- Day 4: High-Entropy Passphrases ---

A new system policy has been put in place that requires all accounts to use a passphrase instead of simply a password. A passphrase consists of a series of words (lowercase letters) separated by spaces.

To ensure security, a valid passphrase must contain no duplicate words.

For example:

• aa bb cc dd ee is valid.
• aa bb cc dd aa is not valid - the word aa appears more than once.
• aa bb cc dd aaa is valid - aa and aaa count as different words.

The system's full passphrase list is available as your puzzle input. How many passphrases are valid?