The Lamp-Brands of Glimmerdeep Delve

No delver goes down into the Glimmerdeep without a brand stamped on their lantern by the Lampwrights' Guild. The Guild has found forged brands among the lanterns. It offers a commission to whoever will build the inspector that reads a brand and names its first fault.

Write inspectBrand(brand). brand is a string.

A well-formed brand is exactly 7 characters long: - characters 1–2: uppercase letters A–Z (the guild mark), - character 3: a hyphen -, - characters 4–7: digits 0–9.

The last digit is a check digit. It must equal the sum of digits 4, 5 and 6 modulo 10.

"Letter" means only the uppercase letters A–Z, so lowercase letters fail. "Digit" means only 0–9.

Apply these rules in this order. Return the verdict of the first rule the brand fails:

1. "wrong length": the brand is not exactly 7 characters. 2. "bad guild mark": character 1 or character 2 is not an uppercase letter A–Z. 3. "missing hyphen": character 3 is not -. 4. "bad number": any of characters 4–7 is not a digit 0–9. 5. "bad check digit": character 7 does not equal (digit 4 + digit 5 + digit 6) modulo 10.

If the brand passes all five rules, return "sound". The return value is always one of these six strings.