Make it finish

Match a string made only of the letter a, from start to end. The corpus includes a long run followed by one character that cannot match — the shape that turns a plausible pattern into a hang — and your answer has to stay inside the step budget on it.

Corpus

Steps0/ 380 · par 190

Every input, what the pattern matched in it, and what each group captured
Input	Match	Steps
	(empty)	3
	(empty)	3
	(empty)	3
	(empty)	3
	(empty)	3
	(empty)	3

Trace

Select an input to step through what your pattern did to it.

Cmd-Enter submits too.