Let $R$ be the region in the accompanying figure.
Fill in the missing limits of integration in the iterated integral
$$ \iint_R f(x, y) \, dx \, dy = \int_a^b \int_c^d f(x, y) \, dx \, dy $$
NOTE: Enter the exact answers.
$a = 0$
$b = 16$
$c = $
$d = $