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: ['1345', 'y', '7221', 'h', 'r', '3255', 'k', 'r', 'j', '8639', '467', 'f', 'k', 'n', 'k', 'j', 'l', 'w', '143', 'w', 'q', '5657', '589']

SOLUTION: f, h, j, k, l, n, q, r, w, y

PROBLEM: ['5611', 'x', 't', 'p', '5711', '7079', '5251', '429', 'z', 'u', '8721', '9321', '79', 'i', '189', '3605', 'k', '445', 'r', 'k', 'o', '2189', '8521', '8849', '2651', 'm', '4149', '1577', '3085', '5275', '6413', '5265', '6089', 'r', 'f', '5013']

SOLUTION: f, i, k, m, o, p, r, t, u, x, z

PROBLEM: ['5511', '1637', 'q', 'a', 'm', '6559', '6227']

SOLUTION:
a, m, q