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: ['815', '6967', '6553', 'r', 'y', '3641', 'q', 'b', '6131', '4289', 'w', '6093', '6055', 'i', 'b', 'y', '5107', 'v', 'g', '9709', 'x', 'i']

Answer: b, g, i, q, r, v, w, x, y


Question: ['x', 'u', 'm', '8089', '9985', 'e', '2927', 'n', '7085', 'q', 'v', 'f', 'p', '5079', '3339', '7871', 'h', '7389', '733', 'e', '3387', 'b', 'x', 'z', '2039', 'u', '59', '5031', '8115', '5447', '3045', 'x', '6591', '9561', '4315']

Answer: b, e, f, h, m, n, p, q, u, v, x, z


Question: ['8091', 'm', '3677', '3045', '3717', '2917', '4529', '8763', 'c', 'i', '4299', 's', '8605', 'n', 's', 'o', 'r', 'h', '897', 'm', '7637', 's', 'j', 'h', 'h', '6503', '1955', '6705', 'd', 'm', 't', '8145', '1547', 'p', '9117', 'i', '2911', 's']

Answer:
c, d, h, i, j, m, n, o, p, r, s, t