Let the line $\mathrm{L}_1$ be parallel to the vector $-3 \hat{i}+2 \hat{j}+4 \hat{k}$ and pass through the point $(2,6,7)$, and the line $L_2$ be parallel to the vector $2 \hat{i}+\hat{j}+3 \hat{k}$ and pass through the point ( $4,3,5$ ). If the line $\mathrm{L}_3$ is parallel to the vector $-3 \hat{i}+5 \hat{j}+16 \hat{k}$ and intersects the lines $\mathrm{L}_1$ and $\mathrm{L}_2$ at the points C and D , respectively, then $|\overrightarrow{C D}|^2$ is equal to :