Let the position vectors of two points A and B be $\overline{\mathrm{a}}+\overline{\mathrm{b}}+\overline{\mathrm{c}}$ and $\overline{\mathrm{a}}-2\overline{\mathrm{b}}+3\overline{\mathrm{c}}$ respectively. If the points P and Q divide AB in the ratio 1:3 internally and externally respectively, they $3\left|\overline{\mathrm{AB}}\right|=$