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: ['4345', '1815', '7973', '6187', 'U', '1133', '8791', '3555', 'i', 's', 'L', 'm', '7695', 'A']

4345, 1815, 7973, 6187, 21, 1133, 8791, 3555, 9, 19, 12, 13, 7695, 1