  The terrestrial planets are believed to have formed by violent collisions of
tens of lunar- to Mars-size protoplanets at time t<200 Myr after the
protoplanetary gas disk dispersal (t_0). The solar system giant planets rapidly
formed during the protoplanetary disk stage and, after t_0, radially migrated
by interacting with outer disk planetesimals. An early (t<100 Myr) dynamical
instability is thought to have occurred with Jupiter having gravitational
encounters with a planetary-size body, jumping inward by ~0.2-0.5 au, and
landing on its current, mildly eccentric orbit. Here we investigate how the
giant planet instability affected formation of the terrestrial planets. We
study several instability cases that were previously shown to match many solar
system constraints. We find that resonances with the giant planets help to
remove solids available for accretion near ~1.5 au, thus stalling the growth of
Mars. It does not matter, however, whether the giant planets are placed on
their current orbits at t_0 or whether they realistically evolve in one of our
instability models; the results are practically the same. The tight orbital
spacing of Venus and Earth is difficult to reproduce in our simulations,
including cases where bodies grow from a narrow annulus at 0.7-1 au, because
protoplanets tend to radially spread during accretion. The best results are
obtained in the narrow-annulus model when protoplanets emerging from the
dispersing gas nebula are assumed to have (at least) the Mars mass. This
suggests efficient accretion of the terrestrial protoplanets during the first
~10 Myr of the solar system.
