def count_consonants(text):
    return len([x for x in set(text.lower()) if x not in 'aeiou' and x.isalpha()])

'''
Complete the function that counts the number of unique consonants in a string
(made up of printable ascii characters).

Consonants are letters used in English other than "a", "e", "i", "o", "u".
We will count "y" as a consonant.

Remember, your function needs to return the number of unique consonants -
disregarding duplicates. For example, if the string passed into the function
reads "add", the function should return 1 rather than 2, since "d" is a duplicate.

Similarly, the function should also disregard duplicate consonants of differing cases.
For example, "Dad" passed into the function should return 1 as "d" and "D" are duplicates.

Examples

"add" ==> 1
"Dad" ==> 1
"aeiou" ==> 0
"sillystring" ==> 7
"abcdefghijklmnopqrstuvwxyz" ==> 21
"Count my unique consonants!!" ==> 7
'''
