11 as the number of levels located above the first one and these flights are simply conveyor belts however in order to prevent the merchandise from falling the belts may be equipped with fixing elements these elements can be rotary flanges separated in a regular way so that the merchandise does not go backwards while ascending or forwards while descending each flight ends in a landing through which a level is accessed via its intake 1 by activating a divertor 14 in the case of this embodiment the belt staircase goes upwards on the side of the levels and downwards on the most external part as for every intake a photoelectric cell and a tag reader are located at the staircase 39 s intake 12 the merchandise enters the warehouse passing through the photoelectric cell and tag reader 12 which act in the same way as the 2 at the intake 1 thus the computer estimates the parcel 39 s length and activates the divertor of the u2018 landing u2019 where the merchandise is supposed to be better placed once the merchandise enters each level the operation is the same as already mentioned to recover the merchandise and due to the actions that take place in its single.