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: ['5957', 'd', 'i', 'b', 'e', '5565', 'c', 'i', '2919']

SOLUTION: b, c, d, e, i

PROBLEM: ['c', 'e', 'c', 'u', '3679', '3883', 't', '831', 'z', '689', 'z', 'c', '7343', '1297', 'd', '4441', '2647', '8479', '2715', '8285', '5575', '4729', 'f', '9823', 'y', '2191', 'k', 'c', '2545', '3047', 'c']

SOLUTION:
c, d, e, f, k, t, u, y, z