Easy# Total Flux 4 Faces

MVCALC-XEWURC

The flux of a vector field $\vec{F}$ through a closed surface $S$ is 2. The surface $S$ consists of 4 faces $A$, $B$, $C$, and $D$.

If the flux through $A$, $B$, and $C$ are 1, $-4$, and 5, respectively, what is is the flux of $\vec{F}$ through $D$?