Among the species given below, the total number of diamagnetic species is _____
H atom, ${\mathrm{NO}}_2$   Monomer, ${{\mathrm{O}}_2}^{-}$   (Superoxide), dimeric Sulphur in vapour phase,  
${\mathrm{Mn}}_3{\mathrm{O}}_4,{\left({\mathrm{NH}}_4\right)}_2\left[{\mathrm{FeCl}}_4\right],{\left({\mathrm{NH}}_4\right)}_2\left[{\mathrm{NiCl}}_4\right],{\mathrm{K}}_2{\mathrm{MnO}}_4,{\mathrm{K}}_2{\mathrm{CrO}}_4$