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', '6153', 'e', 'C', '6445', '1229', '9463', 'U', 'O', 'd', 'h', 'r', '1221', 'q', 's', '151']

21, 6153, 5, 3, 6445, 1229, 9463, 21, 15, 4, 8, 18, 1221, 17, 19, 151