short_str in long_str

[Truman]

I'm following tutorial and one of the problems to solve is this one:
1. [ ] get user input for a single word describing something that can be read save in a variable called can_read
e.g. - "website", "newspaper", "blog", "textbook"
2. [ ] get user input for 3 things can be read
save in a variable called can_read_things
3. [ ] print true if the can_read string is found
in the can_read_things string variable

can_read = input("add1: ")
can_read_things = input("add3: ")
print(can_read_things.find(can_read))

I wrote this code with add1 = book and add3 = book notebook textbook but when I run the code receive outcome 0. Help is appreciated.