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: ['6213', 'n', 'v', '5881', '5461', 'h', '3543', 'c', '3933', 'C', '5153', 'R', '4549', '4721', '3609', 'I', 'D', 'B', 'C', 'K', 'r', '7417', 'Z']

6213, 14, 22, 5881, 5461, 8, 3543, 3, 3933, 3, 5153, 18, 4549, 4721, 3609, 9, 4, 2, 3, 11, 18, 7417, 26