CD&Cassette player code

Hi
My dad bought Daewoo Leganza 1999 CDPlayer&Cassette player ,it asks for code.

ModelNO.AKD-0636VA.
PartNO.96331534

Thanks

I have a 2000 laganza
model akd-0636vs
s/n#10806407
I know the code is 7400 , but i don't know how to put it in.can SOMEONE help?