china double entry visa and stopover

hi, I plan on visiting Hong Kong, Macau, Shenzhen and Beijing.
I will be entering china a total of three times:
1. 3 hour stopover in Beijing on the way to Hong Kong
2. a day trip to Shenzhen from Hong Kong
3. a weekend in Beijing (flying from Hong Kong to Beijing).
my question is - does my 3 hour stopover in Beijing qualify as an entry to china? if I get a double entry one to China, will that be enough (the double entry will cover my trip to Shenzhen and Beijing, but not the stopover), or do I need the multiple entry type (of course the multiple entry is preferred, but i want to know if it is NECESSARY).
THANK YOU!!