day2-puzzle1.txt

--- Day 2: Password Philosophy ---

Their password database is corrupted.

They have created a list (your puzzle input) of the passwords in the corrupted database,
and the rules for a valid password at the time that password was set.

For example, suppose you have the following list:

1-3 a: abcde
1-3 b: cdefg
2-9 c: ccccccccc

Each line gives the password policy and then the password.
The password policy indicates the lowest and highest number of times a given letter
must appear for the password to be valid.

For example, 1-3 a means that the password must contain 'a' at least 1 time and at most 3 times.

In the above example, 2 passwords are valid.

The middle password, cdefg, is not;
it contains no instances of b, but needs at least 1.

The first and third passwords are valid: they contain one 'a' or nine 'c', 
both within the limits of their respective policies.

How many passwords are valid according to their policies?