Itc/npcs 4 digit code) ????????????????

Hello everyone,

i am filing annual accounts and annual returns of a pvt ltd company engaged in advertising business- in news papers/magazies  ( ad agency). In form 23aca it is compulosry to menion the Details of principal products/servies and (ITC/NPCS 4 digit code)

I read the instruction and got the list from mca site but it is not 4 digit code but 5 digit code (99836) and further subcategory )998361/998362 etc are there.

My question : how to write the 4 digit code and file the form ACA ? waiting for the views of the experts.