Thank you. Found additional details from IRS, see below. I cannot claim them as dependents.
Substantial Presence Test
You will be considered a U.S. resident for tax purposes if you meet the substantial presence test for calendar year 2016. To meet this test,you must be physically present in the United States on at least:
1. 31 days during 2016, and
2. 183 days during the 3-year period that includes 2016, 2015, and 2014, counting:
a. All the days you were present in 2016,and
b. 1/3 of the days you were present in 2015, and
c. 1/6 of the days you were present in 2014.
