An easy mnemonic for the number of days in each month

Most of us have probably learnt the Knuckle mnemonic, the following poem, or some variant of it at some point to remember the number of days in each month:

Thirty days has September,
April, June, and November,
All the rest have thirty-one,
Save February at twenty-eight,
But leap year, coming once in four,
February then has one day more.

It's cute but mostly unnecessary. It doesn't take a whole lot to remember that February has 28 days in a common year, and 29 days in a leap year, which happens every four years.

So the only valuable info in that poem is this section: September, April, June, and November which still requires some effort to recall. To make it stick, I came up with my own mnemonic back in middle school: SNAp June, and I've relied on this successfully for years.

In numeric format, these months correspond to 4 6 9/11. (Update: @Someone on HN suggested the following cool mnemonic: If you write these numbers in Roman, they each have exactly two unique letters and have a nice pattern to them: IV/VI IX/XI.)

All the other months consist of 31 days.