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.

Ex Input:
['5785', 'c', 'f', '7087', 'd', '9225', 'm', 'g', '4639', '7165', '3445', '3813', 'p', 'i', '719', 's', 'g', '6423', '9563', 'w', 'm', '8659', '8809', '4105', '3923', '465', '5637', '5547', 'h', 'v', '9453', '4009']

Ex Output:
c, d, f, g, h, i, m, p, s, v, w


Ex Input:
['3797', '6117', 'x']

Ex Output:
x


Ex Input:
['1543', 'x', 'x', '341', '7421', 'i', '5521', '8933', 'k', 'f', '21', '2619', 'd', '579', '7301', '9731', 'm', 'c', 'i', 'h', '4467', 'v', '269', 'l', '5035', 'm', '2651', 'g', 'h', 'f', '2469', 'a', 't']

Ex Output:

a, c, d, f, g, h, i, k, l, m, t, v, x