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: ['g', 'h', 'g', 'g', 's', 'h', '2849', '2705', '1185', 'x', '5789', '8221', 'e', 'x', 'g', 'b', '4903', 'q', '1563', 'r', 'k', 't', '9047', 'p', 'p', '9397', 'u', '7473', 'f', 'o', 'y', '1957', '1039', '9905', 'i', '4829', 'q', 'w', 'k', 'p', 't', '563', 'g', 'l']

SOLUTION: b, e, f, g, h, i, k, l, o, p, q, r, s, t, u, w, x, y

PROBLEM: ['g', '4165', 'n', 'w', 'n', 'e']

SOLUTION: e, g, n, w

PROBLEM: ['k', '8665', '9257', 'x', 'x', '1269', 'x', '7133', '5817', 'n', '8467', 'w', 'y', 'q', '3161', '8073', '9327', '4051', 'k', '4919', '623', 'd', 'f', '3581', '2699', '4035', '6891', '1735', 'i', 'w', '5423', 'i', 'f']

SOLUTION:
d, f, i, k, n, q, w, x, y