Two particles are simultaneously thrown from the top of two towers as shown. Their velocities are $2 \mathrm{m} {\mathrm{s}}^{-1}$ and $14 \mathrm{m} {\mathrm{s}}^{-1}$. Horizontal and vertical separations between these particles are $22 \mathrm{m}$ and $9 \mathrm{m}$ respectively. Then the minimum separation between the particles in the process of their motion in meters is ($g = 10 \mathrm{m} {\mathrm{s}}^{-2}$)