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: ['i', 'y', '8339', 'd', 'b', '7471', '6577', '9037', '4503', '6287', '1439', '8863', '9201', '2661', 'x', 'l', 'v', 'w', 'a', 'f', '8885', '519', '7631', 'g', '7203', '8605', '2429', '9165']

SOLUTION: a, b, d, f, g, i, l, v, w, x, y

PROBLEM: ['t', 'x', '1699', '8727']

SOLUTION: t, x

PROBLEM: ['w', 'w', '7245', '2075', '4731', '7255', 'p', 'z', '2451', 'l', '479', '8397', '1029', 'b', '4733', 's', 'g', 'i', 'u', 'h', 'x']

SOLUTION:
b, g, h, i, l, p, s, u, w, x, z