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: ['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: ['l', 'y', '1879', 'g', 'j', 'm', '861', 'n', 'o', '8405', '2333', '9135', 'u', '3757', '627', 'x', 'd', 'u', 'f', '1133', '2745', '1643', 'k', '1371', 'u', 'g', '4071', '8851', 'g', 's', 'a', '7445', '65', '6205', '1903', 'a', 'p', 'i', 'j', 'i', 'a', 'v']

SOLUTION:
a, d, f, g, i, j, k, l, m, n, o, p, s, u, v, x, y