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: ['6699', 'n', '5811', '1929', '2251', '3553', '8431', 'j', '7015', 'W', 'K', 'j', 'r', '9903', 'K', 'O', 'G', '5495', '9939', 'F', '2759', 'B', 'Z', '5351', 'S', 'E', 'P', '2799', '3321', 'Y', '5425', 't']

6699, 14, 5811, 1929, 2251, 3553, 8431, 10, 7015, 23, 11, 10, 18, 9903, 11, 15, 7, 5495, 9939, 6, 2759, 2, 26, 5351, 19, 5, 16, 2799, 3321, 25, 5425, 20