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: ['h', 'v', '1263', 'y', '3299', 'd', 'a', 'h', 's', '2007', '7597', '1015', 'k', '6643', '6959', 'g', 'u', 'd', '5737', 'n', 'z', 'y', 'b', 'g', '9059', '7349', 'j', 'w', 'i', 'z', 'p', '5809', 'x', '4421', 'g', '6399', '3965']

SOLUTION: a, b, d, g, h, i, j, k, n, p, s, u, v, w, x, y, z

PROBLEM: ['u', '9249', 'u', 't', 'm', 'm', 'n', 'w', '8617', '2729', 'i', 'l', '2971', '3227', 'b', '9017', '4711', 'i', 't', 'r', 'a', 'a', '1701', '6397', '4535', '9167', '6039', '6111', '849', 'p', '8197', '2645', '5147', 'u', 'l', '7419', 'w', 'w', 'k', 'x', 'c', '3377', '4015', '1297', 'f']

SOLUTION: a, b, c, f, i, k, l, m, n, p, r, t, u, w, x

PROBLEM: ['f', 'x', 'l', '4541', 'p', '9881', 'k', '3157', '631', '4581', 'j', '3695', '7401', 'x', 'v', 'h', 'b', 'b', 'z', 'q', '5455', 'x', '9513', 'i', '2053', '3239', 'l', '7111', 'x', '7999', '4345', 'a', '2719', '9647', 'd', 'b', 'v', '7061', '8215', 'b', '7953']

SOLUTION:
a, b, d, f, h, i, j, k, l, p, q, v, x, z