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: ['e', 'z', '5199', 'x']

SOLUTION: e, x, z

PROBLEM: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']

SOLUTION: j, t, w

PROBLEM: ['4395', '7077', 't', '5341', 's', '2869', 'y', '6051', '9121', 'r', 'l', '2967', 'v', 'f', '5349', '6849', 'k', '8947', '4975', 'j', 'j', '4939', '3295', 'i', '8875', '4323', '2215', '8473', '633', '6895', '8995', '505', 'o', '7185', 'm', 't']

SOLUTION:
f, i, j, k, l, m, o, r, s, t, v, y