Vector Algebra

If \(\mathrm{D}, \mathrm{E}\) and \(\mathrm{F}\) are the mid-points of the sides \(\mathrm{BC}\), \(\mathrm{CA}\) and \(\mathrm{AB}\) of triangle \(\mathrm{ABC}\) respectively, then \(\overline{\mathrm{AD}}+\frac{2}{3} \overline{\mathrm{BE}}+\frac{1}{3} \overline{\mathrm{CF}}=\)