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: ['4261', '3467', '1073', 'U', 'z', '7249', 't', 'K', '2503', 'g', '9761', 'c', '5125']

4261, 3467, 1073, 21, 26, 7249, 20, 11, 2503, 7, 9761, 3, 5125