Two solid shapes are constructed using the same base radius r and same total height H. Shape A is a cylinder with a hemisphere on top. Shape B is a cylinder with a cone on top. If the height of the cylindrical part in Shape A is twice the radius (hcyl=2r), and the height of the cylindrical part in Shape B is also 2r, determine which shape has the greater volume and by how much (in terms of π and r3).