How many different monochloro products (constitutional isomers) are possible when propane reacts with $\mathrm{Cl}{}_2$ in the presence of light?

Propane has two kinds of hydrogen: six equivalent primary H on the two $\mathrm{CH}{}_3$ groups and two equivalent secondary H on $\mathrm{CH}{}_2$. Hence $\mathrm{CH}{}_3\mathrm{CH}{}_2\mathrm{CH}{}_2\mathrm{Cl}$ and $\mathrm{CH}{}_3\mathrm{CHClCH}{}_3$ form, giving 2 products.