Among the following complexes, the total number of diamagnetic species is $\_\_\_\_$ .
$ \left[\mathrm{Mn}\left(\mathrm{NH}_3\right)_6\right]^{3+},\left[\mathrm{MnCl}_6\right]^{3-},\left[\mathrm{FeF}_6\right]^{3-},\left[\mathrm{CoF}_6\right]^{3-},\left[\mathrm{Fe}\left(\mathrm{NH}_3\right)_6\right]^{3+} \text { and }\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+} $
[Given, atomic number: $\mathrm{Mn}=25, \mathrm{Fe}=26, \mathrm{Co}=27$; en $=\mathrm{H}_2 \mathrm{NCH}_2 \mathrm{CH}_2 \mathrm{NH}_2$ ]