Guess the missing item from this list: α-8, α-4, α-3, α-5, β-6, α-0, α-7, α-9, β-4, β-1, α-2, α-1, α-6, β-2, β-5, β-0.
Directly answer with only one item. Item format should match the list format. Provide no explanation. Answer format: "{item}."