  We explicitly show that the Poisson bracket on the set of shear coordinates
introduced by V.V. Fock in 1997 induces the Fenchel--Nielsen bracket on the set
of gluing parameters (length and twist parameters) for pairs of pants
decomposition for Riemann surfaces with holes $\Sigma_{g,s}$. We generalize
these structures to the case of Riemann surfaces $\Sigma_{g,s,n}$ with holes
and bordered cusps.
