Apple juice (viscosity =1.6cP) is being filtered through a 2 m² filter under a constant pressure. The juice has solid concentration of 0.04 g.mL^-1 in filtrate. The total pressure drop is 325.33 kPa. The values of cake and filter medium resistance are 1.85×10¹¹ m.kg^-1 and 3.50×10¹¹ m^-1, respectively. The time required to filter 800 litres of juice is ______ hour. (Answer in integer)