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: ['b', 'd', '8153', 'u', '3695', '5317']

SOLUTION: b, d, u

PROBLEM: ['5161', 'v', 'y', '6005', 'y', 'l', '5451', 'z', 'j', 'd', '4597', '9319', '1241', 'g', 'f', 'b', 'g', '683', '763', 'm']

SOLUTION: b, d, f, g, j, l, m, v, y, z

PROBLEM: ['x', 'k', 'e', 'a', '8655', 'b', 't', 'g', '8667', 'i', '1073', '3243', 't', 'v', '753', '6861', '5839', '7117', '8109', 'h', '3155', 'r', 'i', '8583', '5993', 'i', 'x', 'o', 'k', 'o', 'v', '2433', 'm', 'e', 'u', '8503', '5159', 'n', '6507']

SOLUTION:
a, b, e, g, h, i, k, m, n, o, r, t, u, v, x