In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.
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Question: ['m', '6537', '4063', '6413', 'k', 'd', '2479', 'p', '2251', 'q', '7079', 'r', 'd', 'p', '3347', '1391', '9847', '4487', 'u', '6951', '5285', '5837', '6747', 'r', 's', 'c', 'x', 'b', 'q', 'y', 'd', '331', '679', 'v', '1919', 'f', 'p', '1267', '3151']

Answer: b, c, d, f, k, m, p, q, r, s, u, v, x, y


Question: ['h', 'g', '4563', 'v', 'm', '107']

Answer: g, h, m, v


Question: ['g', '4199', '8145', 'r', '8465', '651', 'x', '9781', '4631', 'z', 'p', 'n', '7911', '8407', 'i', '4355', '339', 'h', '7557', 'f', '1089', '2185', 'q', 'n', 'b', '1979', '8399', 'o', 'n', 'k', 's', 'z', 'z', 'q', 'd', '4109', 'f']

Answer:
b, d, f, g, h, i, k, n, o, p, q, r, s, x, z