What is the formula of the compound Prussian blue formed in the test of nitrogen ?

${\mathrm{Fe}}^{2+}\stackrel{{\mathrm{H}}^{+}}{⟶}{\mathrm{Fe}}^{3+}+{\mathrm{e}}^{-}; {6\mathrm{CN}}^{-}+{\mathrm{Fe}}^{2+}⟶{\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{4-}$

$3{\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{4-}+4{\mathrm{Fe}}^{3+}⟶\underset{\mathrm{Prussian} \mathrm{blue} \left(\mathrm{X}\right)}{\stackrel{\mathrm{III}}{{\mathrm{Fe}}_4}[\stackrel{\mathrm{II}}{\mathrm{Fe}}{\left(\mathrm{CN}\right)}_6{]}_3}$

${\mathrm{Fe}}^{3+}+3{\mathrm{CNS}}^{-}\to \underset{\text{Blood red (Y and Z)}}{\mathrm{Fe}{\left(\mathrm{CNS}\right)}_3}$