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: ['x', 'i', 'r', '6011', 't', 'f', 'b', 'i', '8367', '4051', '1459', 'f', '5583', '9609', 'l', 'q', 'g', '8443', 'o', '8697', '7053', '8325', 'k', '7021', 'q', 'm', '6899', '9981', '8985', 'i', 'j', '8043', 'k', '535', '7603', '7629', 'k', '2779', 'g', '2049', 'x', 'd', '8527', 'k', 'q']

Answer: b, d, f, g, i, j, k, l, m, o, q, r, t, x


Question: ['j', '425', '6223', '6631', 'y', '7649', 'r', 'a', '7933', '7947', 'l', 'l', '8755', 'g', 'b', '3351', '49', 'v', 'm', 'x', '3291', '1007', '1401', 'z', 'q', 'a']

Answer: a, b, g, j, l, m, q, r, v, x, y, z


Question: ['b', 'f', '55', 'o', '7695', 'j', '3161', '8501', '6139', '3491', '619', '3813', 'f', 'n', 'u', '611', '2833', 'q', '2441', '6435']

Answer:
b, f, j, n, o, q, u