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', 'y', 'c', '3211', '9245', '8459', '8521', '5781', 'w', 's', 'd', '5299', 'a', 'y', 'g', 'm', '6435', '8605', 'e', 'h', '6871', 's', '387', 'l', '5829', 'e', 'd', '9545', '2945', 'k', 'v', 't', '8449', '2199', 'm', '2599', '1489', '6623', 'x', 'l']

SOLUTION: a, c, d, e, g, h, k, l, m, r, s, t, v, w, x, y

PROBLEM: ['u', '1805', 'l', 'l', '5449', 'r', '4471', 'a', 'u', 'c', 'q', '6463', '6717', '7025', '9359', 'q', 'h', '1989', '5497', 'h', 'd', 'c', '135', '5737', '1235', 'v', 'u', 'g', 'p', 't', '9223', '8289', '4489', 'n']

SOLUTION: a, c, d, g, h, l, n, p, q, r, t, u, v

PROBLEM: ['2301', '179', '2433', '7599', '5009', 't', '6547', '8329', '8351', '6823', '4417', '9605', '8523', '79', 'g', 'a', '6635', '7045', 'i', 'q', '7785', 'j', '2123', '5351', 'o', '1969', '7175', 'u', 'z', 'i', '8369', 'm', '6965', '2315', '6707', '3443', '9617', '8135', 'f']

SOLUTION:
a, f, g, i, j, m, o, q, t, u, z