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: ['8741', 'h', '2147', '373', 'c', 'r', '2639', '3511', '1393', 't', '7173', 'f', '9371', '7659', 'q', '4799', 'f', '1967', '1905', '8783', 'i', 'n', 'z', '6395', 'u', 'i', '1493', '1395', '1909', '477', 'i', '8547', '393', '2203', '6893', 'y', '2085', '6445', '7753', '4027', 'h', 'y', '7963']

SOLUTION: c, f, h, i, n, q, r, t, u, y, z

PROBLEM: ['d', 'g', '9019', '9987', '8713', '9513', 'a', '2043', 'd', '5817', 'w', 'd']

SOLUTION: a, d, g, w

PROBLEM: ['5965', '7959', '2353', '8039', '3697', '8299', '6033', 'j', '1061', 'e', '6593', 'g', 'g', '4931', 'l', 'g', '7825']

SOLUTION:
e, g, j, l