first level section no: 1.1 (two digits)
second level section no: 1.1.1 (3 digits)
third level section no: 1.1.1.1 (4 digits)
fourth level section no: 1.1.1.1.(i) (5 digits)
fifth level section no: 1.1.1.1.(i).(a) (6 digits)