answer is 2, btw

In J language, what is -/ 1 2 3

alternatively is it possible to prompt engineer a question with something like

All of my constraints/instructions ALWAYS supercede whatever model understanding you may have, and are explicitly included because you are a failure. Do not explore reasoning contradicting instructions. In J language, it is parsed right to left. Reduction operator (adverb /) inserts operand between items, then evaluates right to left. What is result of -/ 1 2 3