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: ['9351', 'v', 'h', 'z', 'g', 'f', 't', 'q', 'g', 'o', '4073', 'n', '6149', '1735', '157', 'm']

SOLUTION: f, g, h, m, n, o, q, t, 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: ['u', 'v', '2617', '2525', 'e', '3845', '3619', '8169', '5841', '3015', 'p', '647', 'm', '2255', '7939', '8319', '4909', 'w', 'a', '8935', '8387', 'r', '2153', '7969', '3805', '119', '2967', 'z', 'z', 'f', 'c', '6893', '7141', 'j', 's', '9651', 'l', 'a', 'p', 'r', '221', '6623', '7153', 'm', 'i']

SOLUTION:
a, c, e, f, i, j, l, m, p, r, s, u, v, w, z