"""
--- 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?
"""
valid = 0
with open('input.txt') as f:
    for phrase in f:
        words = phrase.strip().split(' ')
        if len(words) == len(set(words)):
            valid += 1

print(valid)
