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: ['d', '5285', 'z', 't', 'i', '719', 'z', 'b', '3603', '4781', 'o', 'g', 'j', 'd', 'r', 'a', 'x', '5829', '4907', '7395', '993', '2109', '1745', '415', '7525', '1029', '7791', '5321', 'h', '6391', 'g', '4613', '9191', 'o', '7365', '1811', '9695', 'w']

SOLUTION: a, b, d, g, h, i, j, o, r, t, w, x, z

PROBLEM: ['f', '9203', 'w', 'f', '3751', '8095', '1319', 'f', '3017', 'r', 'y', '8221', '2715', '9959']

SOLUTION: f, r, w, y

PROBLEM: ['7583', 'z', '6927', '7813', 'a', 'f', 'i', '4699', 'h', '2615', 'p', '6843', 'w', '4097', 'x', 's', 'r', '5629', '8719', 'y', '6883', 'o']

SOLUTION:
a, f, h, i, o, p, r, s, w, x, y, z