A storage room measures 400 inches in length, 200 inches in width and 200 inches in height. It needs to be modified, by extending its length, to hold at least 2000 special boxes. The box measures 20 inches in height, 20 inches in width and 40 inches in length. To meet this goal, what is the minimal length that needs to be added? Need at least inches more in length for the storage room.