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:
['l', '1213', 'm', 'k', '7825', '3501', '2397', '2313', 'v', '4119', 'h', 't', '6137', 'l', '9851', 'q', '9661', 'b', 'z', '1437', '1759', 'l', '611', '5085', '4443', 'n', 'u', 'b', '2511', '6023', '7157', 'n', '9921', 'o', 'a', 'o', 'w', 't', 'o', '1607', '6751', 'n', 'b']
answer:
a, b, h, k, l, m, n, o, q, t, u, v, w, z


question:
['9555', '5983', '1853', 'c', 'z', 't', 'p', '9041', 'd', '5919', '1621', '345', 's', '2647', '4261', '8611', 'w', 'x', 'p', '9103', '2599', '5101', '9261', 'k', '7437']
answer:
c, d, k, p, s, t, w, x, z


question:
['1539', 'l', '3309', '5789', 'w', '9835', '1529', 'c', '5829', 'a', '2049', '9859', '6037', 't', 'm', 'p', 'o', 'j', 'b', 'y', '4803', 'y', 'w', '7465', 'j', 'w', 'v', '6597', 'd', 'w', 'g', '7069', 's', 'b', 's', '3011', 'a']
answer:

a, b, c, d, g, j, l, m, o, p, s, t, v, w, y


