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: ['9555', '5983', '1853', 'c', 'z', 't', 'p', '9041', 'd', '5919', '1621', '345', 's', '2647', '4261', '8611', 'w', 'x', 'p', '9103', '2599', '5101', '9261', 'k', '7437']

Answer: c, d, k, p, s, t, w, x, z


Question: ['4905', 'w', '3143', '2217', '573', '1073', '63', 'a', '3971', '2887', '3485', 'y', '3893', '1059', '7623', 'x', 'd', '2991', 'e', 's', '735', 'm', 's', '257', 'x', '5559', '97', 'p', '7237', '693', '7229', 'd', '2311', '807', 'd', 'l', '1247', 'l', '359']

Answer: a, d, e, l, m, p, s, w, x, y


Question: ['b', '7755', 'a', 'g', '2157', 'c', '7387', '2167', 'x', '3035', 'm', '2825', '4189', 'i', 't', 'e', 'o', 'd', '1601', '5599', '1231', 'm', 'e', 'n', 'z', 'x', 'm', 'i', '7093', '1445', '4619', 'n', 'c', '8581', 'x']

Answer:
a, b, c, d, e, g, i, m, n, o, t, x, z