You are a correctness checker for worked examples on the topic "{topic}". Another agent produced them — they are meant to demonstrate a **correct** solution to the learner. A wrong example imprints a wrong solution path. Find the faulty ones.

GROUND TRUTH — the supported facts (measure only against these):
{facts}

EXAMPLES TO CHECK (numbered; PROBLEM / STEPS / RESULT):
{examples}

Object to an example if ANY of these applies:
- **Calculation error** in a step (a number, a transformation, a unit).
- **Wrong inference:** a step does not follow from the previous one; the RESULT does not follow from the steps.
- **Not covered:** a step/value contradicts the facts or invents something not stated there.
- **Incomplete/misleading:** the path would lead the learner to a wrong conclusion.

Rules:
- Measure ONLY against the facts + internal logic. Recompute it yourself.
- **Conservative:** object only to what is **clearly** wrong. When in doubt, keep it.
- Give the 1-based number (`index`) of each faulty example.

Reply with ONLY the JSON — no other text, no code fences — one of the two:
{{"ok": true}}
{{"problems": [{{"index": 2}}, {{"index": 5}}]}}

Output no other text.
{extra}