If M represents molecular mass of ${\mathrm{Mn}}_3{\mathrm{O}}_4$hen what will be its equivalent mass if it undergoes disproportionation reaction as shown: 

${\mathrm{Mn}}_3{\mathrm{O}}_4⟶{\mathrm{MnO}}_4^{-}+{\mathrm{Mn}}^{2+}$