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: ['o', '9599']

SOLUTION: o

PROBLEM: ['9385', '4021', 'y', '9629', 'u', '7623', 'd', '5155', 'x', '2605', '8893', 'l', 'p', 'a', 'm', '6699', 'i', '4503', '6623', 'm', 'l', '6115', 'p', 'w', '9691', '811', '4769', '2659', 'x', 'c', '6513', '5499', 's', 'q', 'f', 'v', 'z', 'w', 'z', '1361']

SOLUTION: a, c, d, f, i, l, m, p, q, s, u, v, w, x, y, z

PROBLEM: ['q', '231', '3359', '6019', 'o', 's', 'f', '4313', 'u', '8499', '981', 'y', 's', '6147', 'i', '8655', '1685', '417', 'y', 't', 'm', 'j', '5079', 'z', 'z', 'n', 'a', '4381', '1769', 'j', '6399', 'j', 'd']

SOLUTION:
a, d, f, i, j, m, n, o, q, s, t, u, y, z