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