Cartridge 56 As 54 HP Deskjet F4180 Printer Ink Cartridges?

HP Deskjet F4180 Printer Ink Cartridges? - cartridge 56 as 54

I recently purchased an HP Deskjet F4180, and I do not need ink cartridges. It says that you need a cartridge for the black # 54 and # 57 in color. But I've never had a # 54 cartridge. All I can find are # 56, including those that came in packages with the No 57. Is it possible to use No. 56 instead of # 54, or can someone tell me where I can find a reasonable # 54 on? Thank you!