  Gravitational waves detected from the binary neutron star (NS) merger
GW170817 constrained the NS equation of state by placing an upper bound on
certain parameters describing the binary's tidal interactions. We show that the
interpretation of the UV/optical/infrared counterpart of GW170817 with kilonova
models, combined with new numerical relativity results, imply a complementary
lower bound on the tidal deformability parameter. The joint constraints
tentatively rule out both extremely stiff and soft NS equations of state.
