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: ['x', 'j', '9747', 'i', '2015', '3505', 'q', 'n', 'h', '3011', 'u', '8043', 'j', 'f', 'd', 'a', 'p', '5817', 'l', 'q', '2275', 'n', '7085', '5373', 'l', 'g', 'b', '8043', '3085']

SOLUTION: a, b, d, f, g, h, i, j, l, n, p, q, u, x

PROBLEM: ['d', 'a', '6931', 'c', 'u', 'z', '9713', 'v', 'm', 'e', 'k', 'o', '9705', 'a', '5373', 'c', '2983', '8097', 'h', '3039', 'g', 'f', 'n', 'v', '853', '8227', '7573', 'j', 'h', 'k', 'o', 'k', '8897', 'd', 'g', 'd', 'd', '4039']

SOLUTION: a, c, d, e, f, g, h, j, k, m, n, o, u, v, z

PROBLEM: ['3769', 'm', '7743', '2465', '2933', 'p', '7025', '2493', 'd', '2565', 'j', '2393', '6281', '8681', '4969', 'u', '7295', '5193', '4851', '8623', 'p', 'z', 't', 'z', 'c']

SOLUTION:
c, d, j, m, p, t, u, z