please give exact answer please

What is the atomic weight of an element if it has 3 isotopes: Isotope 1 has a mass of 34.987 and an abundance of 0.45000, Isotope 2 has a mass of 36.976 and an abundance of 0.33000, Isotope 3 has a mass of 38.886 and an abundance of 0.22000 ? Report to 5 significant figures. Don't round until the end, this requires the exact