A crude oil pipeline 500 km long with 400 mm outside diameter and 8 mm wall thickness is used to transport 600 m3/ hr of product from a crude oil terminal at San José to a refinery located at La Paz. Assuming the crude oil has a specific gravity of 0.895 and viscosity of 200 SSU at 20°C, calculate the total pressure drop due to friction in the pipeline. If the MAOP of the pipeline is limited to 10 MPa, how many pumping stations will be required to transport this volume, assuming flat terrain? Use the modified Colebrook-White equation and assume a value of 0.05 mm for the absolute pipe roughness.