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: ['4371', '9499', 'e', 'w', '9969', '8367', '2897', '1745', 'i', '7049', '9773', 'h', '9649', 'u', '4673', '8513', '8547', 'z', '1995', '7739', '2215', '171', 'c', '7527', '2479', 't', '5223', 'p', '2313', '3243', '2281', 'r', 'c']

SOLUTION: c, e, h, i, p, r, t, u, w, z

PROBLEM: ['o', '4167', 'b', '1651', '8327', '9219', 'o', 'v', '5841', '6057', 'i', 'q', 'o', 'r', 'a', '7069', 'y', 'h', 'd', '3775', 'j', 't', '3663', '55', '7117', 'e', 'u', 'm', '931', '5777', '8773', '4891']

SOLUTION: a, b, d, e, h, i, j, m, o, q, r, t, u, v, y

PROBLEM: ['8949', 'o', '8133', 'v', '6387', '5505', '8097', '9385', '4643', 'a', '9645', '4665', 't', 'y', 'q', '4715', '6581', '9067', '7699', '9091', '5125', 'n']

SOLUTION:
a, n, o, q, t, v, y