The time limit is 12s.

you're probably missing something then, people here are pretty good at spotting the best solutions

Having the same issue, I don't understand the instruction. It says return '' if more than one possible pair of a,b values, yet the tests ask us to return two pairs of a,b values?

Edit:
Honestly, just ignore that criteria and anything about the amount of a,b pairs, just make a solution which returns the a,b pairs quickly and you'll pass.

please read this on how to post: https://docs.codewars.com/training/troubleshooting#post-discourse

In VSC you can only try the basic tests, so your code may pass the basic ones and fail on the more complete tests in Attempt. Or actually there is a difference you did not figure out between your output and the expected result. This kata has been completed more than 86000 times, so it is very improbable the issue comes from the tests.

If you need more help please say which language you're using and give clear elements to understand which is the problem you are facing (add a spoiler flag if you give elements of solution).

It tells me that there is an error in 4 examples but in my vsc the solution is correct

Please read this: https://docs.codewars.com/training/troubleshooting and print the input to debug your code when it fails, for instance, one your code failed was: "QWUBQQWUBWUBWUBIWUBWUBWWWUBWUBWUBJOPJPBRH". Don't forget marking your post as having spoiler content and using markdown formatting.