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: ['g', '6867', '7965', '3313', 'k', '1827', '7337', 'u', '1209', '5145', 'w', 'h', '9059', 'u', 'b', '3189', '2837', 'k', 'y', 'e', 'b', '4479', '541', '7103', 'h', 'm', '2177', '6377', '3993', '7167', 'q', '2145', '5007', '9135', '5331', 'e']

SOLUTION: b, e, g, h, k, m, q, u, w, y

PROBLEM: ['6627', '8037', 'q', 'e', 'j', 'p', '9613', '9317', 'm', 'm', '5345', 'f', '8105', '5665', '4175', '4793', '3707', 'i', 'b', '6745', '747', '8329', '1481', 'b', '8949', 'n', '4803', '1359', '3533', 'f', '543', '3003', '6943']

SOLUTION: b, e, f, i, j, m, n, p, q

PROBLEM: ['2339', '7159', '1741', 'u', '1913', 'n', 's', 'q', '7829', 'u', 'q', 'r', '6667', 'b', 'a', '573', 'h', '1443', 'q', 'b', '6013', 'w', 'r', '4329', 'o', '4495', '575', 'n', '5455', 'd', '3423', '2741', '7121', '401', 'b', 'o', 'd', 'a', 'b', '1167', '157', 's', '4239', 'd', '4657']

SOLUTION:
a, b, d, h, n, o, q, r, s, u, w