At a certain University, CS students must choose a 7 character password consisting of the16 hexadecimal characters (0-9, A-F). The systems administrator hated the 1970’s pop bandABBA and requires that all passwords exclude the 4 contiguous letters making up the wordABBA from appearing anywhere in the password. A1B2B3A or AB123BA would be ok (theletters in the word ABBA are not contiguous), but ABBA123 and 1ABBA23 are disallowed. How many legal passwords are possible? (