what is the formula for the compound that crystallizes with a cubic closet packed array of sulfur ions and that contains zinc ions in 1/8 of the tetrahedral holes and aluminum ions in 1/2 of the octahedral holes

What is the formula for the compound that crystallizes with a cubic closest packed array of sulfur ions, and that contains zinc ions in 1/8 of the tetrahedral holes and aluminum ions in 1/2 of the octahedral holes? (If a number appears as a subscript, write it next to the element regularly. ex: AsF 5 would be put in the blank as AsF5)