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: ['n', '6615', 'r', 'q', '3803', '4641', '9775', '7719', 'n', '6571', '2723', '6919', 'e', 'f', '1919', '6963', '2581', 'y', '713', 'w', 'w', 'w', 'l', 's', '3993', '9563', '9365', '9277', '103', '2737', 'y', '6005', '9763', 'p', '261']

SOLUTION: e, f, l, n, p, q, r, s, w, y

PROBLEM: ['7653', 'n', '697', '4565', 't', '7275', '2429', '1365', '7059', 'o', '8053', 'j', '2837', '957', '851', 'z', 'd', 'd', 'y', 'c', '7467', 'o', 'i', '9519', 'q', 'g', '7911', 't', 'g', '3439', '5821', '8433', 'k', 'z', 's', 'g', '685', 'i', 't', 'r', '6881']

SOLUTION: c, d, g, i, j, k, n, o, q, r, s, t, y, z

PROBLEM: ['h', '87', 'm', 'i', '3461', '7513', 'e', 's', 'b', 'c', 'q', '1515', '5731', 'a', 'x', '4017', '3757', 'g', '9457', 'x', 'm', '8961', 'o', '4507', 'a', 'v', '2763', 'o', 'l', '4613', '4303', '4925', '5143', '5941', '1047', 'v', '3069', 'y', '5147']

SOLUTION:
a, b, c, e, g, h, i, l, m, o, q, s, v, x, y