DNA reminder

You probably know that the bases in DNA are adenosine, paired with thymine, and cytosine, paired with guanine.
You probably also know that in each base pair there is one purine and one pyrimidine, and one has a single ring and one has a double ring.

The question is How to remember this?

Suggestion:

Remember: "Purines:2 rings" ( I find it helps if you say it in a funny voice).

Then the letter Y: pYrimidines are thYmine and cYtosine

This only works with RNA if you spell uracil as uracYl !