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: ['U', '6461', '5917', 'n', '3743', 'e', 'F', 'J', 'K', 'k', '5241', 't', '7025', '6059', 'J', '3721', '5563', '739', '7503', 'j', 'B', 'p', 'i', 'H', '1595', '3627', 'u', '3797', '3991', '193', 'f', '8915', '4225', '2337']

21, 6461, 5917, 14, 3743, 5, 6, 10, 11, 11, 5241, 20, 7025, 6059, 10, 3721, 5563, 739, 7503, 10, 2, 16, 9, 8, 1595, 3627, 21, 3797, 3991, 193, 6, 8915, 4225, 2337