TASK DEFINITION: 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.
PROBLEM: ['5039', '2227', 't', 'o', '3313', 'm', 'v', '637', '6773', 'v', 'c', 'l', 'y', 'u', '3823', '9669', 'k', 'h', '3589', 'b', 'i', '3833', 's', 'm', '8201', 'u', '3143', 'k', '4111', '9769', '425', '4339', '209', 'c', 'c', '669', '8201', 'u', '7443', '2387', '6919', 'b', 'b', '2873']

SOLUTION: b, c, h, i, k, l, m, o, s, t, u, v, y

PROBLEM: ['j', 'a', 'z', 'h', '4129', '4159', 'm', 'o', 'o', '1193', '2905', '3083', 'q', 't', 'm', 'o', '673', '7547', 'n', 'c', 'r', 't', '2897', '4959', 'z', '2377', 'y', '7977', 'u', 'b', 's', 'w', 'e', 'd', '8051']

SOLUTION: a, b, c, d, e, h, j, m, n, o, q, r, s, t, u, w, y, z

PROBLEM: ['p', '1153', 'm', 'c', 'x', '381', '1987', 'a', '4059', 'f', 'g', '1275', '5727', 'r', 'c', 'v', '6019', 'w', '4339', 't', '7789', 'g', 'l', 'e', '9607', '8213', 'q', 'z', '3651', '2913', 'g', 'c']

SOLUTION:
a, c, e, f, g, l, m, p, q, r, t, v, w, x, z