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: ['5193', 'h', 'm', '703']

SOLUTION: h, m

PROBLEM: ['j', 's', 'z', 'v', '5401', 'u', '8859', 'i', 'l', 'a', 'p', 'v', 'v', 'o', '3969', '4091', 'y', '6827', '1799', '5163', 'd', 'w', '4795', '5167', 'x', 'q', '2903', '1171', '5279', '449', '7901', 'u']

SOLUTION: a, d, i, j, l, o, p, q, s, u, v, w, x, y, z

PROBLEM: ['9907', 'b', 'v', 'r', '1007', '2015', 'z', 'a', 'q', 'q', '4671', 'm', '6507', 'r', '7169', 'c', 'c', '4253', '8237', 'z', '8227', '4521', '9377', '8109', '1893', '4639', 't', '5631', 'a', 'x', 'v', 't', 'c', '8653']

SOLUTION:
a, b, c, m, q, r, t, v, x, z