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: ['3499', 'v', '5447', 'U', '7765', 'b', '5447', 'V', 'f', '4783', 'W', 'F', '4449', '5961', 'f', 'r', 'y', 'O', 'f', '8643', '5735', '9157', 'p']

3499, 22, 5447, 21, 7765, 2, 5447, 22, 6, 4783, 23, 6, 4449, 5961, 6, 18, 25, 15, 6, 8643, 5735, 9157, 16