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: ['9113', '3625', 'u', '8189', '3649', '259', '5539', '1583', 'g', '4037', 'y', 'v', '8337', 'd', 'q', 'j', 'c', 'h', 'p', '1601', 'z', 'c', 'n', '1767', '1679', '1805', 'm', '4469', '2487', '6015', '973']

SOLUTION: c, d, g, h, j, m, n, p, q, u, v, y, z

PROBLEM: ['n', 'g', 'u', '2873', 'k', '4411', 'w', '8179', 'w', 'w', 'f', 'g', 'e', '7837', '3055', 'z', 's', '6037', 'n', '1479', 'c', '5311', 'i', 'w', 'z', '1891', '9663', 'y', 'f', 'h']

SOLUTION: c, e, f, g, h, i, k, n, s, u, w, y, z

PROBLEM: ['3003', 'k', 'b', '7653', '4325', '5447', '4811', '6641', 'a', 'f', 'd', '5273', '3715', 'n', 'g', '5909', '7473', '2567', '2771', 'a', '5739', 'v', '3585', '7191', 'm', 'm', 'f', 'x', 'n']

SOLUTION:
a, b, d, f, g, k, m, n, v, x