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: ['6737', 'g', '9985', '5257', 'k', 't', '7863', 'y', '8319', 'l', 'o', '6505', '6531', 'z', '3055', '2943', '3625', 'h', '4867']

Answer: g, h, k, l, o, t, y, z


Question: ['r', 't', '3539', 'z', 't', '6055', 'r', '5787', '8469', 'p', 'h', '9729', 'z', '1637', '5873', 'c', '3597', '4411', 's', 'k', 'q', '6471', '5375', 'e', 'v', 'i', '7425', 'h', '9079', 'd', '1585', '6011', 'x', '5669', '5219', '4951', '4765', '8285', '2811', 'c', '1805', '6463']

Answer: c, d, e, h, i, k, p, q, r, s, t, v, x, z


Question: ['6613', '9535', 'a', 'g', 'a', 'd', '7139', 'k', '2899', 'l', 'o', '5527', '333', '9331', 'f', 's', '1779', '5995', '4313']

Answer:
a, d, f, g, k, l, o, s