This paper presents a model that explains the low mass of Mars and the structure of the asteroid belt in the early Solar System. The authors propose that Jupiter's migration, initially inward to 1.5 AU, followed by outward, led to a truncated planetesimal disk at 1 AU, which formed the terrestrial planets over 30-50 million years. This scenario explains the mass ratio between Earth and Mars and the compositional differences in the asteroid belt. The inward migration of Jupiter scattered S-type asteroids inward, while C-type asteroids were scattered outward and later encountered during the outward migration. The model also suggests that C-type asteroids, which are rich in volatiles, could have provided water to Earth. The results are consistent with the current asteroid belt composition and support the idea that Jupiter's migration played a crucial role in sculpting the inner Solar System.This paper presents a model that explains the low mass of Mars and the structure of the asteroid belt in the early Solar System. The authors propose that Jupiter's migration, initially inward to 1.5 AU, followed by outward, led to a truncated planetesimal disk at 1 AU, which formed the terrestrial planets over 30-50 million years. This scenario explains the mass ratio between Earth and Mars and the compositional differences in the asteroid belt. The inward migration of Jupiter scattered S-type asteroids inward, while C-type asteroids were scattered outward and later encountered during the outward migration. The model also suggests that C-type asteroids, which are rich in volatiles, could have provided water to Earth. The results are consistent with the current asteroid belt composition and support the idea that Jupiter's migration played a crucial role in sculpting the inner Solar System.