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: ['5611', 'x', 't', 'p', '5711', '7079', '5251', '429', 'z', 'u', '8721', '9321', '79', 'i', '189', '3605', 'k', '445', 'r', 'k', 'o', '2189', '8521', '8849', '2651', 'm', '4149', '1577', '3085', '5275', '6413', '5265', '6089', 'r', 'f', '5013']

SOLUTION: f, i, k, m, o, p, r, t, u, x, z

PROBLEM: ['c', '4881', '6893', '3729', 'j', '2385', 'q', 'v']

SOLUTION: c, j, q, v

PROBLEM: ['b', 't', 'o', '301', 'k', 'y', '8745', 'c', '9259', 'i', 'd', 'g', '3225', 'k', '8345', '4651', '9237', 'n', '5555', '7139', '8197', '6347', 'h', '5209', 'b', '4761', 'x', '1967', 'z', '3199', 'q', 't', '8849', 'p', 'q', 'p', 'j', '2393', '4555', 'z', 'x', 'j', 'm']

SOLUTION:
b, c, d, g, h, i, j, k, m, n, o, p, q, t, x, y, z