In the rectangular coordinate plane,
$$\begin{aligned}
& f ( x ) = x ^ { 2 } - 2 x \\
& g ( x ) = - x ^ { 2 } + 4 x
\end{aligned}$$
The shaded region between the graphs of these functions and the x-axis is given below.
Accordingly, what is the area of the shaded region in square units?\\
A) $\frac { 17 } { 3 }$\\
B) $\frac { 19 } { 3 }$\\
C) $\frac { 20 } { 3 }$\\
D) $\frac { 22 } { 3 }$\\
E) $\frac { 23 } { 3 }$