Let S={(x, y) ∈ N × N: 9(x-3)^2+16(y-4)^2 ≤ 144} and T={(x, y) ∈ R × R:(x-7)^2+(y-4)^2 ≤ 36}. Then n(S ∩ T) is equal to \ \ \ \

Let $\displaystyle S=\left\{(x, y) \in \mathbb{N} \times \mathbb{N}: 9(x-3)^2+16(y-4)^2 \leq 144\right\}$ and $\displaystyle T=\left\{(x, y) \in \mathbb{R} \times \mathbb{R}:(x-7)^2+(y-4)^2 \leq 36\right\}$. Then $\displaystyle n(S \cap T)$ is equal to \_\_\_\_