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', '4969', 'W', 'C', '1115', 'd', 'g', 'Q', 'j', '651', 'l', '4629', 'p', 'A', '3183', 'I', '6149', '5975', '3843', '3117', '5569', '4979', '9773', '7753', 'W']

21, 4969, 23, 3, 1115, 4, 7, 17, 10, 651, 12, 4629, 16, 1, 3183, 9, 6149, 5975, 3843, 3117, 5569, 4979, 9773, 7753, 23