If the vectors $\vec{A}=a_{x}\hat{i}+a_{y}\hat{j}+a_{z}\hat{k}, \vec{B}=b_{x}\hat{i}+b_{y}\hat{j}+b_{z}\hat{k}$ and $\vec{C}=c_{x}\hat{i}+c_{y}\hat{j}+c_{z}\hat{k}$ are defining the vector $\vec{T}=\vec{A}-\vec{B}+\vec{C}$ then the z-component of the vector $T_{z}$ is