  In this paper we present first LHCb results on charmless charged two- and
three-body $B$ meson decays. In particular, using the first picobarn of
integrated luminosity, LHCb observed the $B^{0}\rightarrow K^{+}\pi^{-}$ and
$B^{+}\rightarrow K^{+}\pi^{+}\pi^{-}$ decays. Such decays provide an
interesting way to determine the angle $\gamma$ of the Unitary Triangle, thanks
to the possible presence of New Physics in the penguin loops.
