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: ['8357', 'x', 'w', '287', 'z', '2733', '1757', 'w', 'g', '1393', '7201', '4931', 'k', '5185', 'x', '6313', '2255', 'z', 'v', '3593', '6191', '4423', 'm', 'k', '3209', '3559', 'c', 'n', 'm', '5461', '2997', '235', '4045', '6597', 'v', 'e', 'p', 'c', 'k', 'd', '5529', '6241', 'u', 'f', '8067']

SOLUTION: c, d, e, f, g, k, m, n, p, u, v, w, x, z

PROBLEM: ['5785', 'c', 'f', '7087', 'd', '9225', 'm', 'g', '4639', '7165', '3445', '3813', 'p', 'i', '719', 's', 'g', '6423', '9563', 'w', 'm', '8659', '8809', '4105', '3923', '465', '5637', '5547', 'h', 'v', '9453', '4009']

SOLUTION: c, d, f, g, h, i, m, p, s, v, w

PROBLEM: ['q', 'p', '1463', '5483', 'o', '4659', '9475', '715', '331', '6839', '9239', 'n', '1813', '477', '4789', 'e', '8751', 'u', '5753', 'f', 'z', '4473', 'g', '2275', 'b', '3347', 't', '2601', 's', '8889', '4003', '1899', 'n', '2637', 'e', 'v', 'g', 'n', '7965', 'o']

SOLUTION:
b, e, f, g, n, o, p, q, s, t, u, v, z