Problem with a numeric field in a INPUT

I am having a problem when trying to use a numeric field in a input command.
when I run the program below, the user id exhibited on the screen is 5 bytes long, instead of 4 bytes as specified in the ‘‘define data’’.
what should I do in order to have a numeric 4-byte long field on the screen, please?

define data 
1 w-userid (n4)

input 'Inform Userid:' w-userid    (ad=u)


The input is showing 5 bytes to allow for a sign if the number is negative. Try:

input 'Inform Userid:' w-userid    (ad=u sg=off)

thanks a lot!
my guess was this sign thing but i didn’t know how to fix it!
thanks again!