TASK DEFINITION: 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.
PROBLEM: ['5463', '5683', 'w', '4071', '3997', 'i', '9677', 'q', 'l', 'v', 'w', '5325', '197', 'g', 'g', '3227', '3477']

SOLUTION: g, i, l, q, v, w

PROBLEM: ['h', '1797', '8211', 'n', 'r', '7707', '2063', '4655', 'x', '5521', '8327', 'g', '7659', 'i', 'x', 'w', '9465', '4625', 'q', '5377', 'r', '225', 'r', 'i', 'e', '4163', 'g', 'g', '3537', 's']

SOLUTION: e, g, h, i, n, q, r, s, w, x

PROBLEM: ['8349', 'v', 'u', '6147', '2767', '2095', '1407', 'i', '285', 'i', 'u', 's', '9909', '353', '4471', '9325', '3919', '113', '4801', '8853', '245', 'n', '6683', 'a', '5987', 'h', 'n', 'k', '8581', 'c', '3027', 'j', 't', 'r', '1603', '9563', '3417', '5703', '5025', 's', 'k', 'o', '273', '3479', 'z']

SOLUTION:
a, c, h, i, j, k, n, o, r, s, t, u, v, z