A vessel completely filled with water has holes $\mathrm{A}$ and $\mathrm{B}$ at depths $\mathrm{h}$ and $3\mathrm{h}$ from the top respectively. Hole $\mathrm{A}$ is a square of side $\mathrm{L}$ and $\mathrm{B}$ is circle of radius $\mathrm{r}$. The water flowing out per second from both the holes is same. Then $\mathrm{L}$ is equal to