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: ['2103', '7937', 'v', '7641', '6609', '269', '4463', '4333', 'c', '8407', '4883', '6283', 'a', '8643', '3365', '1929', 'v', 'o', '2107', '7453', '9157', '5581', '5187', 'f', 'k', '8227', '6295', 'b', 'y', '4995', '1187', 'k', 'n', 'p', 'z', '8165', 'n', '7345', 'l']

SOLUTION: a, b, c, f, k, l, n, o, p, v, y, z

PROBLEM: ['7917', '2295', 'q', 'v', '9373', 'w', 'n', 'q', '5803', 'g', 'k', 'm', '2167', 'k', '6425', 'x', 'g', '341', 't', 'u', '8829', 'h', '4333']

SOLUTION: g, h, k, m, n, q, t, u, v, w, x

PROBLEM: ['y', '5895', '1227', 'm', 'w', 'd', '969', '1275', 'd', 'j', '6225', 'w', 'u', '1903', 'm', '9533', 'd', '1247', 'l', 'u', '9439', 'r', '4231', 'm', 'v', 'z', '9129', '6733', '1147', 'y', '7575', 'a', '1555', 'v']

SOLUTION:
a, d, j, l, m, r, u, v, w, y, z