The general formula of amines is

Amines are the functional groups represented by $-{\mathrm{NH}}_2$. If amine group attached to one carbon atom, it is primary amine. If it attached to two carbon atom, it is secondary and if amine attached to three carbon atoms it is called  tertiary amine group. The general formula of amines is ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}+3}\mathrm{N}$. For example methylamine having formula ${\mathrm{CH}}_3{\mathrm{NH}}_2$.