Non-vulgar alternative to “Don't care a ____” [closed]

I am writing a poem for school. The verse with the word I need to change is this:

7 hours is too long
In much too short a day
You really don’t care if you get an answer wrong
Because you don’t care a _____ about radioactive decay

The only thing I can think of is the word shit, but that word is too offensive. I have tried looking for inoffensive alternatives at Real Life English's Not so Offensive Alternatives to Bad Words in English, and wordhippo but these alternatives do not sound great, especially in a poem.

I also searched for don't care a ___ on the free dictionary by Farlex's idioms website and "don't care a fig" came up, alongside some other suggestions I tried from the autofill suggestions. Most worked literally, but I am looking for a more clever and poetic word or words that could be used in a way that relates to my poem. I am not just looking for any old answer. I do not want you to simply search for "don't care a…" on google. I want suggestions that fit creatively into my poem.

One option for a word is whit¹ :

the smallest part or particle imaginable

Don't care a whit² is even an idiomatic phrase:

didn't care at all.
Sally thought Joe liked her, but he didn't care a whit about her.
I don't care a whit what you do with my old clothes.

¹ Webster's Third New International Dictionary s.v. whit²
2 The McGraw-Hill Dictionary of American Idioms and Phrasal Verbs s.v. didn't care a whit

How about 'don't care a bit' it rhymes with your sh... word.

Here's a link to 'not a bit'; 'I don't care a bit' is also idiomatic.

https://idioms.thefreedictionary.com/not+one+bit

A traditional expression for this is don't give/care a fig. Cambridge Dictionaries says it's old-fashioned, but I think the meaning should still be clear in context even for folks who haven't heard it. I would recommend using the don't give a fig form for maximum impact.

Jot

"Because you don’t care a jot about radioactive decay."

This may be UK only usage though. Not sure.

http://www.dictionary.com/browse/jot:

noun

2. the least part of something; a little bit: I don't care a jot.

Idioms

3. not a jot or tittle, not a bit; not at all: The world situation matters not a jot or tittle to him.

lick

I've definitely heard "don't care a lick about [something]", it's a folksy Huckleberry Finn kind of thing to say.

Among the various listings in dictionary.com:

lick

[...]

noun

[...]

9. Informal.

[...]

a small amount: I haven't done a lick of work all week.