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: ['781', 'k', 'U', 'a', '4015', 'q', '8635', 'q', 'h', 'n', 'f', '7941', 't', '9885', 'k']

781, 11, 21, 1, 4015, 17, 8635, 17, 8, 14, 6, 7941, 20, 9885, 11