A bakelite beaker has volume capacity of $500 \mathrm{cc}$ at $30°\mathrm{C}$. When it is partially filled with ${\mathrm{V}}_{\mathrm{m}}$ volume (at $30°\mathrm{C}$)  of mercury, it is found that the unfilled volume of the beaker remains constant as temperature is varied. If ${\gamma }_{\text{bester }}=6\times {10}^{-6}0°{\mathrm{C}}^{-1},$ where $\gamma$ is the coefficient of volume expansion, then  ${\mathrm{V}}_{\mathrm{m}}$ (in $\mathrm{cc}$ ) is close to $\dots$