The North American Student Tracking Association (NASTA) maintains and operates on multiple lists of n students. Each student is identified by a unique 8-digit code, called StudentIDentificationCode (SIDC); (e.g. # SIDC: 47203235). Some of these student lists are local to villages, towns and remote areas, where n counts only to few hundred students, and possibly less. Others are at the urban cities or provincial levels, where n counts to tens of thousands or more. NASTA needs your help to design a clever “student tracking” ADT called CleverSIDC. Keys of CleverSIDC entries are long integers of 8 digits, and one can retrieve the keys/values of an CleverSIDC or access a single element by its key. Furthermore, similar to Sequences, given a CleverSIDC key, one can access its predecessor or successor (if it exists).