For a certain mammal, researchers have determined that the mesiodistal crown length of deciduous mandibular first molars is related to the post conception age of the tooth as L(t) = - 015t~ + 1.43t -7.2, where L(t) is the crown length (in millimeters) of the molar t weeks after conception. Find the maximum length in mesiodistal crown of mandibular first molars during weeks 30 through 60. The maximum length is mm. (Round to three decimal places as needed.)