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: ['l', '6313', '3199', 'w', '249', '8747', '7391', '3871', '173', 'x', 'o', '8647', '4413', '3645', '6123', '701', 'q', '2147', '4289', '7333', '533']

Answer: l, o, q, w, x


Question: ['g', '6867', '7965', '3313', 'k', '1827', '7337', 'u', '1209', '5145', 'w', 'h', '9059', 'u', 'b', '3189', '2837', 'k', 'y', 'e', 'b', '4479', '541', '7103', 'h', 'm', '2177', '6377', '3993', '7167', 'q', '2145', '5007', '9135', '5331', 'e']

Answer: b, e, g, h, k, m, q, u, w, y


Question: ['6269', '1389', '5267', '1261', '9585', 'f', 'z', 'a', 'i', '4529', 'n', '9289', 'n', 'h', 'm', 'z', 'y', '8635', '2187', '9731', '5613', '2125', '2063']

Answer:
a, f, h, i, m, n, y, z