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: ['3921', 't', 'z', '2797', 'y', '7675', '4537', 'a', 'B', '2825', 'X', 'a', '5481', '7343', 'x', 'w', '1389', 'e', '411', 'u', 'D', 'l', '7971', 'M', '9395', '6381', '2879', '9679', '8939', '7755', 'O', 'Z', '6181', '4609', '3989', '1253', '5297', '8257', 'T']

3921, 20, 26, 2797, 25, 7675, 4537, 1, 2, 2825, 24, 1, 5481, 7343, 24, 23, 1389, 5, 411, 21, 4, 12, 7971, 13, 9395, 6381, 2879, 9679, 8939, 7755, 15, 26, 6181, 4609, 3989, 1253, 5297, 8257, 20