A grit chamber of rectangular cross-section is to be designed to remove particles with diameter of $\text{0.25 mm}$ and specific gravity of $2.70$. The terminal settling velocity of the particles is estimated as $\text{2.5 cm/s}$. The chamber is having a width of $\text{0.50 m}$ and has to carry a peak wastewater flow of $9720\text{ m$^{3}$/d}$ giving the depth of flow as $\text{0.75 m}$. If a flow-through velocity of $\text{0.3 m/s}$ has to be maintained using a proportional weir at the outlet end of the chamber, the minimum length of the chamber (in $\text{m}, \textit{in integer}$) to remove $\text{0.25 mm}$ particles completely is ____________________