instruction:
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.
question:
['o', '9599']
answer:
o


question:
['x', 'u', 'm', '8089', '9985', 'e', '2927', 'n', '7085', 'q', 'v', 'f', 'p', '5079', '3339', '7871', 'h', '7389', '733', 'e', '3387', 'b', 'x', 'z', '2039', 'u', '59', '5031', '8115', '5447', '3045', 'x', '6591', '9561', '4315']
answer:
b, e, f, h, m, n, p, q, u, v, x, z


question:
['d', '5285', 'z', 't', 'i', '719', 'z', 'b', '3603', '4781', 'o', 'g', 'j', 'd', 'r', 'a', 'x', '5829', '4907', '7395', '993', '2109', '1745', '415', '7525', '1029', '7791', '5321', 'h', '6391', 'g', '4613', '9191', 'o', '7365', '1811', '9695', 'w']
answer:

a, b, d, g, h, i, j, o, r, t, w, x, z