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: ['b', 'r', '7073', '6451', 'y', '1333', '9693', '3661', '6861', '7539', 'U', 'Q']

2, 18, 7073, 6451, 25, 1333, 9693, 3661, 6861, 7539, 21, 17