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: ['r', 's', '3409', 'a', 'e', '6855', 'i', 'n', '8655', 's', 't', '8401', 'u', '9603', '8815', 'q', 'a', 'x', 'i', '8455', 'e', '5877', '3917', 'p']

SOLUTION: a, e, i, n, p, q, r, s, t, u, x

PROBLEM: ['d', 'g', '9019', '9987', '8713', '9513', 'a', '2043', 'd', '5817', 'w', 'd']

SOLUTION: a, d, g, w

PROBLEM: ['j', '9079', '8947', 'w', 'm', '929', '765', '2513', '7009', '1547', '3739', 'g', '2653', 'u', 'q', 't', '195', 'o', '6483', '2727', 'h', '1593', '459', 'z', '3401', 't', '49', 'h', '2655', 'e', 'p', 'm', 'j', '817', 'e']

SOLUTION:
e, g, h, j, m, o, p, q, t, u, w, z