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: ['i', '4447', 'g', 'o', 'j', 'p', 'l', 'q', 'o', '8777', 'r', 'v', '961', '6083']

SOLUTION: g, i, j, l, o, p, q, r, v

PROBLEM: ['3611', '6825', 'j', 'e', 'r', 'a', '8889', 'y', 'x', 'k', '2651', '4545', '2289', 'r', 'q', '3163', 'a', 'i', 'j', 't', 'b', '2673', '4307', 'q', '5839', 'w', 'g', '6221', 'g', 'h', 'h', '5815', 'n', '3551', '7709', 'z', '2281', '7987', 'w', 'a', '2319', '3337', '3409']

SOLUTION: a, b, e, g, h, i, j, k, n, q, r, t, w, x, y, z

PROBLEM: ['6981', 't', 'm', '1265', '6949', 'j', '6507', '311', 'c', '9963', '9555', '4623', '7429', '2657', '193', '5369', 'x', 'w', '6581', '7703', 'e', '4419', 'p', '1825', '2689', '9623', '9909', 'w']

SOLUTION:
c, e, j, m, p, t, w, x