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: ['f', 't', '2135', '8397', '6361', '389', '2253', 'x', 'p', '4833', '5785', 'x', '1811', '9639', '5739', '175', '3231', '5931', 'r', 'c', 'g', 'h', 'p', '909', 'p', '587', 'a', 'a', 'h', 'q', 's', '5945', '4911', 't', 'h', '7517', 'p', '3177', 'h', 'u', '3577', '7055', 'l']

SOLUTION: a, c, f, g, h, l, p, q, r, s, t, u, x

PROBLEM: ['2161', '8009', '3057', 'r', '3897', 'd', 'j', '2727', 'b', '3231', 'i', '9227', '393', '5799']

SOLUTION: b, d, i, j, r

PROBLEM: ['f', '3053', 'g', 'x', 'k', 'p', 'v', 'n', '8685', '5619', '3755', 'p', '5841', '5217', 'p', '53', '1217', 'r', 'e', '5595', 'n', 'q', '5345', 'j', '7927', 's', '2453', 'n', '8931', 'r', '1767', '3003', 'q', 'v', '9759', 'u', '8115', '4109', 'o', 'f', '1921', '8427', '345', '9775']

SOLUTION:
e, f, g, j, k, n, o, p, q, r, s, u, v, x