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: ['4973', '1189', 'W', 'N', 'F', '4423', '7915', 'j', '3723', 'N', '6987', 'o', '2565', '5341', 'u', '7891', '2189', 'c', '5603', '6447', 'l', '1503', 'K', '3125', 'P', 'l', 'P', '7715', '5587', '4871']

4973, 1189, 23, 14, 6, 4423, 7915, 10, 3723, 14, 6987, 15, 2565, 5341, 21, 7891, 2189, 3, 5603, 6447, 12, 1503, 11, 3125, 16, 12, 16, 7715, 5587, 4871