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.

Q: ['587', '3903', 'z', 'l', 'k', '5693', 'x', '1695', 'c', '3185', 'g', '9491', '8185', '1285', '2533', '6825', '3187', '6039', 'e', '251', 'w', '7741', '9573']

A: c, e, g, k, l, w, x, z
****
Q: ['o', 'd', '6495', '5211', '341', 'v', '385', 'v', 'g', 'v', 'l', '7631', '2675', 't']

A: d, g, l, o, t, v
****
Q: ['u', 'g', '2007', 's', '2773', '29', '1581', 'l', 'y', 'k', '5011', '9439', 'r', 'z', '7187', '6527', '7241', '2539', '6115', 'd', 'm', 'w', 't', '9955', '8083', '4973', 'b', '5887', 'a', 'p', 'a', 'c', '5129', 'i', '27', '285', '3243', '4057', 'a']

A:
a, b, c, d, g, i, k, l, m, p, r, s, t, u, w, y, z
****