20 g hemoglobin in a 1 L aqueous solution (A) at 300 K is separated from pure water by semi permeable membrane. At equilibrium the height of solution in a tube dipped in a solution (A) is found to be 80.0 mm higher than the tube dipped in water. The molar mass of hemoglobin is ______ kg mol$^{-1}$. (Nearest integer)
(Given : $g=10 \text{ m s}^{-2}$, $R=8.3 \text{ kPa dm}^3 \text{ K}^{-1}\text{mol}^{-1}$, density of solution $= 1000 \text{ kg m}^{-3}$)}