Guess the missing item from this list: α-5, α-4, α-2, α-0, α-1, α-6, β-2, β-4, β-1, α-3, α-7, β-0, β-6, β-5, α-8, β-3.
Directly answer with only one item. Item format should match the list format. Provide no explanation. Answer format: "{item}."