Evaluate $\int\!\!\int\!\!\int _{\mathcal{W}} f(x,y,z)\,dV$ for the function $f$ and region $\mathcal{W}$ specified:

$$f(x,y,z)=12(x+y)\quad \mathcal{W}: y\le z \le x, 0\le y\le x , 0\le x\le 1$$ $\int\!\!\int\!\!\int _{\mathcal{W}} (12(x+y) ) \,dV =$