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