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: ['l', 'o', 's', '7411', '7847', '2557', '1977', '2863', '2325', '4177', '4183', '4241', '1005', '1137', '1371', 'v', 'p', 'a', '2453', 'l', '6315', 'l', '6463', 'n', '7645', '9669', '5411', '1631', '5995', 'z', '227']

SOLUTION: a, l, n, o, p, s, v, z

PROBLEM: ['o', '1217', '449', 'n', 'e', 'o', 't', '9043', '1925', '5687', '7197', '7943', 'u', '5053', 'q', 'e', '89', 'l', 'h', '3083', '4295', 'o', 'n', '6309', '743', 'n', 'j', '2105', 's', '6845', 'p', 'p', '1355', '3757', 'v', 'f', '961', '4623', '4633', 'p', '4593', 'p', '7337', 'o', 'u']

SOLUTION: e, f, h, j, l, n, o, p, q, s, t, u, v

PROBLEM: ['4205', 'p', '7875', '9421', 'u', 's', '6669', 'u', '6027', '2575', '2063', 'd', 's', '6963', 'f', 'q', 'w', 'y', 'b', '8751', 'e', '4957', 't', '2253', '4487', 'a', '1589', '9565', '9403', 'e', 'c', '2663', '6581', '2539', '9045', '5825', '105', 'i', '5731', '7897', '7', 'd', '8305']

SOLUTION:
a, b, c, d, e, f, i, p, q, s, t, u, w, y