In the formula in paragraph 3 the value of D_y" is given by the formula–

${\mathrm{D}}_{\mathrm{y}}^{\mathrm{"}}={\mathrm{A}}_{\mathrm{y}}^{\mathrm{"}}-{\mathrm{B}}_{\mathrm{y}}^{\mathrm{"}}+{\mathrm{C}}_{\mathrm{y}}^{\mathrm{"}}-{\mathrm{E}}_{\mathrm{y}}^{\mathrm{"}}-{\mathrm{F}}_{\mathrm{y}}^{\mathrm{"}}+{\mathrm{D}}_{\mathrm{y}}^{\mathrm{"}}$