An alkene ‘X’contains five C – C$\sigma$ bonds, twelve C – H $\sigma$  bonds and one C – C $\pi$ bond. ‘X’ on reductive ozonolysis gives two distinct aldehydes as the products Stereoisomers are subjected to ozonolysis separately. If the number of isomeric alkenes which exist for ‘X’ [including stereoisomers] is x, the value of $(x-9)$ is ____.