The plane truss shown in the figure has $13$ joints and $22$ members. The truss is made of a homogeneous, prismatic, linearly elastic material. All members have identical axial rigidity. A to $\mathrm{M}$ indicate the joints of the truss. The truss has pin supports at joints $\mathrm{A}$ and $\mathrm{L}$ and roller support at joint $\mathrm{K}$. The truss is subjected to a $10 \mathrm{kN}$ vertically downward force at joint $\mathrm{H}$ and a $10 \mathrm{kN}$ horizontal force in the rightward direction at joint $\mathrm{B}$ as shown.
The magnitude of the reaction (in $\mathrm{kN}$ ) at the pin support $\mathrm{L}$ is $\_\_\_\_\_\_$ (rounded off to $1$ decimal place).