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.
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Question: ['m', '6537', '4063', '6413', 'k', 'd', '2479', 'p', '2251', 'q', '7079', 'r', 'd', 'p', '3347', '1391', '9847', '4487', 'u', '6951', '5285', '5837', '6747', 'r', 's', 'c', 'x', 'b', 'q', 'y', 'd', '331', '679', 'v', '1919', 'f', 'p', '1267', '3151']

Answer: b, c, d, f, k, m, p, q, r, s, u, v, x, y


Question: ['v', '5433', 'v', '6749', '7491', 'i', 'm', 'e', '5815', '8423', '833', '7359', 'm', 'i', 'f', 'u', 'p', 'j', 't', '3171', '6165', 'q', 'a', '9475', 'm', 'q', '5995', '8443']

Answer: a, e, f, i, j, m, p, q, t, u, v


Question: ['5099', 'r', '2379', '109', 's', 'y', '1419', 'f', 'y', 'y', '3885', '4429', '2235', 'h']

Answer:
f, h, r, s, y