The system shown in the figure is in static equilibrium. The spring is massless and has a spring constant of $\mathrm{K}=1 \mathrm{kN} / \mathrm{m}$. The free length of the spring is $1$ m . All bodies in the system except the spring are rigid and have mass of $\mathrm{M}=1 \mathrm{~kg}$. All surfaces are frictionless and pin joints are ideal. The elongation of the spring $\text{(in mm, rounded off to the nearest integer)}$ in this configuration is __________. Take the acceleration due to gravity $g=10 \mathrm{~m} / \mathrm{s}^{2}$.
