I want to know the answer to the following question:
How many satellite constellations does the BeiDou Navigation Satellite System have?
All the background I'm provided with is that "The BeiDou Navigation Satellite System (BDS, simplified Chinese: 北斗卫星导航系统; traditional Chinese: 北斗衛星導航系統; pinyin: Běidǒu wèixīng dǎoháng xìtǒng) is a Chinese satellite navigation system.". Is that enough to answer the question?
Answer: no