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: ['2381', '2865', '4821', 'n', 'u', 's', 'p', 'v', 'v', 'n', '1349', '7903', 'm', '193', 't', 'p', 'c', '3521', 'a', 't', '8281', 'i', '151', '4783', 'm', '3387', '9551', 'z', 'q', 'v', '4549', '4411', 'u', '8735', '2645', '359', '2871', '5923', '5071', 'c', '9843', 'i']

SOLUTION: a, c, i, m, n, p, q, s, t, u, v, z

PROBLEM: ['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']

SOLUTION: l, y, z

PROBLEM: ['325', 'h', '1027', 't', 'c', 'n', 'q', '6575', 'n', '4177', '6343', '3013', 'x', 'l', 'j', 'n', 'v', 'q', '8647', 'a', '223', '8411', 'v', '2813', 'e', '2237', '7321', 'a', 'e', '9431', 'n', 'y', '2945', '2709', 'x', '9505', 'b', '1499', '9103']

SOLUTION:
a, b, c, e, h, j, l, n, q, t, v, x, y