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: ['6495', '2259', '8213', 'm', 'y', '3377', 'q', 'i', '1299', 's', 'w', '4331', 'h', '5459', '4059', '6637', '8069', '5367', '6025', 'l', 'v', '4503', 'd', 'x', 'w', '5067', '9019', 'd', '7919', '7299', 'v', '8957', 'v', '5341', '2617', '8169', 'n', 'y']

SOLUTION: d, h, i, l, m, n, q, s, v, w, x, y

PROBLEM: ['l', '7111', 'd', 'e', 'h', 'z', 'x', '5673', 'v', '8255', 'i', 'z', 'c', 'i', '4287', 'q', '9293', '9137', 'p', 'n', 'o', 'n', '7883', '6453', '7355', '8769', 'y', '9153']

SOLUTION: c, d, e, h, i, l, n, o, p, q, v, x, y, z

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