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: ['7149', '3915', 'k', 'Y', 'z', 'P', '775', 'v', 'U', '233', 'm', '2939', 'O', '6787', '7717', 'U', '8531', '5071', 'j', '7839', 'S', 'W', 'K', '3689', '8907', '7721', '9099', 'U', 'U', '53', '4025', 'J', '7179', '7587']

7149, 3915, 11, 25, 26, 16, 775, 22, 21, 233, 13, 2939, 15, 6787, 7717, 21, 8531, 5071, 10, 7839, 19, 23, 11, 3689, 8907, 7721, 9099, 21, 21, 53, 4025, 10, 7179, 7587