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: ['g', 'p', '2925', 'n', 'o', 'y', '6381', 'l', '4963', 'g', 'm', 'u', 't', '9389', '3787', '7713', '1251', '779', 'i', 'w', '9869', 'y', 'y', '3881', 'k', 't']

Answer: g, i, k, l, m, n, o, p, t, u, w, y


Question: ['3821', '385', 'y', '8457', '6623', 'g', '5923', 'a', '7193', 'v', 'm', '8915', 'v', '5873', 'p', 't', 'w', 'y', '3617', 'h', 'w', 'j', '8047', 'u', '2271', 'v', 'a', '2181', 's', '1051', 'b', 'a', '9967', '987', 'z', '2255', '6349', '1249', '1397', 'q']

Answer: a, b, g, h, j, m, p, q, s, t, u, v, w, y, z


Question: ['f', 'd', '6985', '1801', 'n', '3693', 'y', 'v', '2897', '9469', 'a', 'f', '463', '893', '1673', 'u', 'm', 'g', 'q', 'l', 'h', 'a', '5357', 'u', '5489', 'k', 'm', '6117', 'u', '7335']

Answer:
a, d, f, g, h, k, l, m, n, q, u, v, y