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.

['8051', 'h', 'g', 's', 't', 'p', 'w', 'x', 's', '8521', 'm', '9719', 'j', 'n', 'i']
g, h, i, j, m, n, p, s, t, w, x

['n', 'w', '6735', '3427', '6115', 'q', '7851', '3645', 'g', '6825', '6515', '4885', 'z']
g, n, q, w, z

['n', '7909', '6043', '6085', 'b', 'v', '3983', 'g', 'e', '4909', '1333', 'e', 'u', 'h', 'r', 'e', 'v', '2771', 'u', '8627', 'p']

b, e, g, h, n, p, r, u, v