Mass function for the three MSs obtained by using the observed LFs of Fig. 12 and the mass-luminosity relations from Pietrinferni et al. (2004, left) and Dotter et al. (2007, right). Continuous black lines are the best-fit straight lines, while grey dotted-dash lines are the maximum- and minimum-slope lines. Note that star counts have been done in mass intervals, by dividing the numbers of stars estimated in luminosity bins by the respective bin widths in mass.