Let ${{\rm{L}}_1}:\frac{{x - 1}}{1} = \frac{{y - 2}}{{ - 1}} = \frac{{z - 1}}{2}$ and ${{\rm{L}}_2}:\frac{{x + 1}}{{ - 1}} = \frac{{y - 2}}{2} = \frac{z}{1}$ be two lines. Let ${{\rm{L}}_3}$ be a line passing through the point $(\alpha ,\beta ,\gamma )$ and be perpendicular to both ${{\rm{L}}_1}$ and ${{\rm{L}}_2}$ . If ${{\rm{L}}_3}$ intersects ${{\rm{L}}_1}$ , then $|5\alpha - 11\beta - 8\gamma |$ equals :