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: ['y', 'p', 'q', '2157', 'b', 'w', '8875', 'k', 'i', 'd', '9743', '4941', 'b', 'p', '9941', '495', 'h', 'i', '839', 'c', 'h', 'f', 'b', 'a', 'k', 'z', '7549', '4149', 'h', 'j', '1947', 't', 'f', 'c', '1243']

SOLUTION: a, b, c, d, f, h, i, j, k, p, q, t, w, y, z

PROBLEM: ['e', 'c', '4241', '2685', 'o', '9859', 'z', '2647', 'b', 'c', 'y', '1985', '5985', '5709', '6655', 'q', 'z', '9933', '6817', '6477', '1837', 'x', 'p', '9251', '3787', 'v', '5741', 'e', 'p', '493', '5949', '5519', 'v', 'g', '1403', 'z', 'h', 'z']

SOLUTION: b, c, e, g, h, o, p, q, v, x, y, z

PROBLEM: ['1785', '2911', '3361', 'e', 'g', '8667', '4061', '8701', 'm', 'd', '8871', '9725', '6125', '6181', '8621', '8709', 'n', '251', '9187', '5823', '5961', '4393', 'c', 'e', 'x', '943', '9091', '6131', '7027']

SOLUTION:
c, d, e, g, m, n, x