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: ['n', '9571', '2983', '7597', 'v', 'y', '1993', '1403', '8309', '7043', 'c', '7329', 'p', '4479', 'p']

SOLUTION: c, n, p, v, y

PROBLEM: ['5463', '5683', 'w', '4071', '3997', 'i', '9677', 'q', 'l', 'v', 'w', '5325', '197', 'g', 'g', '3227', '3477']

SOLUTION: g, i, l, q, v, w

PROBLEM: ['p', 'm', 'p', '1753', 'l', 'c', '7747', '393', 'd', '9659', 'n', 'u', 'z', 'c', '4949', '2973', '3503', 'i', 'm', 'o', '8117', 's', 'c', '7553', 'o', 's', '1831', 'd', 'y', 'h', 'g', '4133', '6505']

SOLUTION:
c, d, g, h, i, l, m, n, o, p, s, u, y, z