If $\overline{\mathrm{a}},\overline{\mathrm{b}}$ and $\overline{\mathrm{c}}$ are vectors with magnitudes 2, 3 and 4 respectively than the best upper bound of $|\overline{\mathrm{a}}-\overline{\mathrm{b}}{|}^2+|\overline{\mathrm{b}}-\overline{\mathrm{c}}{|}^2+|\overline{\mathrm{c}}-\overline{\mathrm{a}}{|}^2$  among the given values is