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: ['u', 'o', 'b', 'b', '5873', 'w', 'v', '4171', '7957', '3501', '2563', 'l', 'q']

Answer: b, l, o, q, u, v, w


Question: ['m', '7807', 'n', 'w', '5097', '1023', '2723', 'u', '3055', '7285', 'f', 'm', 'w', '5197', '9743', '7519', '4451', 'c', 't', '1939', '5847']

Answer: c, f, m, n, t, u, w


Question: ['1863', '3833', 'w', 'v', '2743', 'd', 'c', 'r', 'l', '1591', '2927', 'z', '5411', '1049', 'p']

Answer:
c, d, l, p, r, v, w, z