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: ['3191', '2655', '239', '2585', '3369', '7815', '5919', '8269', '5633', 'x', '8085', '2909', 'y', '2465', 'i', '1579', 'u', '2371', 'l', '1949', '51', 'e']

SOLUTION: e, i, l, u, x, y

PROBLEM: ['p', 'g', 'q', 'e', '8045', '9999', '9555', '7995', '7195', 'z', 't', '5223', '3699', 'i', '4797', '3817', 'x', 'y', 'w', 'o', '8915', '7803', 'n', '1117', 'c', '9647', 'p', 'e', '9669', '4845', '9255', '4545', '3693', '6871', 'w', '4327', '3285', 'k', 'f', 'x', 'i', 'b', '5967', '6601']

SOLUTION: b, c, e, f, g, i, k, n, o, p, q, t, w, x, y, z

PROBLEM: ['c', '4243', 'z', '2199', '8557', 'y', 'w', '3737', '321', '4267', 'x', 'm', '7915', 'x', '6975', '1091', 'y', 'y', '2953']

SOLUTION:
c, m, w, x, y, z