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: ['789', '3603', '3517', '5831', 'z', 'q', 'w', 'l', '5701', '9503', '8169', '1123', 'e', '529', 'j', 'z', 'l', 'o', '3705', 'o', '5131', '6063', 'c', 'j', '6275', '7701']

SOLUTION: c, e, j, l, o, q, w, z

PROBLEM: ['d', '1625']

SOLUTION: d

PROBLEM: ['i', '6223', '2633', 'c', '5101', '4689', '2519', 'b', '4123', '7497', 'v', 'v', 'w', 'g', 'o', 'i', 'n', 'b', '9203', 'y', 'u', 'd', '5529', '5745', '9853', 'v']

SOLUTION:
b, c, d, g, i, n, o, u, v, w, y