A heavy trolley is moving horizontally with a velocity of v m/s w.r.t. earth. A man starts running from one end of the trolley with a velocity 1.5v m/s w.r.t. the trolley. After reaching the opposite end, the man turns back and continues running with a velocity of 1.5v m/s w.r.t. trolley in the backward direction. If the length of trolley is L then the maximum displacement of the man with respect to earth will be