Even Numbers in Two Families

If $J = \{ 2,4,6,\dots,2018, 2020\}$, $E = \{3,6,9,\dots, 2016, 2019\}$, and $F = \{5,10,15,\dots,2015,2020\}$, how many elements are there in the set $J \cap (E\cup F)?$