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: ['9113', '3625', 'u', '8189', '3649', '259', '5539', '1583', 'g', '4037', 'y', 'v', '8337', 'd', 'q', 'j', 'c', 'h', 'p', '1601', 'z', 'c', 'n', '1767', '1679', '1805', 'm', '4469', '2487', '6015', '973']

SOLUTION: c, d, g, h, j, m, n, p, q, u, v, y, z

PROBLEM: ['3627', '2051', '3203', 'c', 'r', 'a', '1453', 'e', 'z', 't', '1093', '4651', 'a', 'f', '8159', '9623', 'l', 't', 'r', '6963', '7071', '8103', '3493', 'y', '2369', '609', '2011', 'f', '187', 'f', 'c']

SOLUTION: a, c, e, f, l, r, t, y, z

PROBLEM: ['673', '4079', 'a', '2001', 'f', 'j', '6687', '2025', '7547', '1285', 'z', '4087', '5649', 'j', 'w', '2453', 'r', '1183', '9277', 'k', '79', 'u', '2839', 'p', '9577', '5137', '2327', 'l', '7373', 'p', 'e']

SOLUTION:
a, e, f, j, k, l, p, r, u, w, z