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: ['9351', 'v', 'h', 'z', 'g', 'f', 't', 'q', 'g', 'o', '4073', 'n', '6149', '1735', '157', 'm']

SOLUTION: f, g, h, m, n, o, q, t, v, z

PROBLEM: ['5089', '6113', 'v', 'l', '5529', 'q', '7499', 'e', 'r', 'c', '5999', '2619', 'a', '2523', '7697', 'j', 'c', '6537', '8313', '5623', '4225', '7677', 'q', 'a', '6559', 'y', 'b', 'm', '7645', '7019', 'r', 'i', '5225', '703', 'i', '6189', 'f', 't', '7553']

SOLUTION: a, b, c, e, f, i, j, l, m, q, r, t, v, y

PROBLEM: ['k', 'c', '5989', 'w', '6209', '8863', '6657', '3421', 'c', '1991', 'h', '9731', '4755', 'g', 'i', 'h', '1071', '3703', '3661', 'r', '4867', '8267', 'p', 'u', 'd', 'h', '9587', 'n', '1907', 's', 'f', 'g', '1299', 'm', '9475', '5069', 's', '2601', '7895', '9263', '1051', '1297', 'd', 'p', '703']

SOLUTION:
c, d, f, g, h, i, k, m, n, p, r, s, u, w