ORIGINAL WORKED REFERENCE

The accepted rows are R1/Ada/2 and R3/Chen/3. R2 fails the seat rule, the later R1 is a duplicate, and R4 lacks a name. Thus 5 input rows = 2 accepted + 3 rejected, with 5 accepted seats. The supplied reference uses only the Python standard library.

CRITICAL CONDITION
No input file is overwritten and every excluded row has an explicit reason.

LIMITS
The tiny case teaches auditable cleaning, not a full production data pipeline or verification of personal information.

This reference is not a learner submission or proof of provider-course completion. See material-verification.json in the production package for actual preparation checks.
