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: ['4423', '8295', 'h', '4881', 'j', 'c', '1185', 'z', 'm', '2725', 'p', '9187', '6275', '1617', '2523', '9879', '4149', '2197', '3909', '5155', '691', 'r', 'e', 'u', 'l', 'd', '1581', '2763', 'c']

SOLUTION: c, d, e, h, j, l, m, p, r, u, z

PROBLEM: ['n', 'h', 'j', '5945', '8511', 'y', '7739', '4717', '2483', 'p', '9545', '7647', '9863', '5591', '5393', 'i', '9225', '589', '1497', 'j', 'm', '2397', 'a', 'd']

SOLUTION: a, d, h, i, j, m, n, p, y

PROBLEM: ['v', '851', '3801', '8967', 'g', '9253', 'r', '5309', '429', 'e', 'j', 'n', 'w', '5675', 'y', 'o', '6497', '7369']

SOLUTION:
e, g, j, n, o, r, v, w, y