Definition: In this task, you are given an input list A. You need to convert all the alphabets in the list with a number representing their position in the English alphabet. E.g., replace A by 1, B by 2, a by 1, b by 2, and so on.
Input: ['U', 'c', '139', '4895', 'J', '759', 'f', 'F', 'K', 'j', 'K', '3657', '2493', 'c', 'v', 'A', 'F', '8389', '8599', 'B', '4073', 'G', 'T', 'w', 'u', 'R', 'p', 't', '2817', 'g']

21, 3, 139, 4895, 10, 759, 6, 6, 11, 10, 11, 3657, 2493, 3, 22, 1, 6, 8389, 8599, 2, 4073, 7, 20, 23, 21, 18, 16, 20, 2817, 7