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.

['1107', 'C', '5921', '7815', '1509', 'l']
1107, 3, 5921, 7815, 1509, 12

['u', 'P', 'n', 'P', '537', '6431', 'u', 'Y']
21, 16, 14, 16, 537, 6431, 21, 25

['P', '9373', '5013', '4909', 'r', 'V', '1255', 'X', '3101', '2877', '1907', 'n', 'v', 'r', '7379', 'h', 'U', '9283', '9327']

16, 9373, 5013, 4909, 18, 22, 1255, 24, 3101, 2877, 1907, 14, 22, 18, 7379, 8, 21, 9283, 9327