  MonChER is a Monte Carlo event generator for simulation of single and double
charge exchange reactions in proton-proton collisions at energies from 0.9 to
14 TeV. Such reactions, $pp\to n+X$ and $pp\to n+X+n$, are characterized by
leading neutron production. They are dominated by $\pi^+$ exchange and could
provide us with more information about total and elastic $\pi^+ p$ and
$\pi^+\pi^+$ cross sections and parton distributions in pions in the still
unexplored kinematical region.
