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: ['4743', '9687', '2887', '4413', 'r', 'w', '2355', 'l', 'd', '453', 'o', 'm', '4351', '5881', '3963', 'g', 'r', 'z', 'q', '7555', 'y', '9555', '405', 'n', 'l', '6733', '1763', 'v', '9925', 'y', '633', '827', 'w']

SOLUTION: d, g, l, m, n, o, q, r, v, w, y, z

PROBLEM: ['a', 'p', 'y', 'l', 'l']

SOLUTION: a, l, p, y

PROBLEM: ['i', '9691', '3287', 'c', 'v', 'k']

SOLUTION:
c, i, k, v