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: ['I', 'm', '6721', '3391', 'D', '6569', 'b', 'I', '6781', '6747', '4849', '7413', 'G', '7339', 'I', '2411', 'K', '9973', 'l', '3535', '2831', 'r', '7443', '3773', '9979', 'E', '929', 'k', 'X', 'y', '5701']

9, 13, 6721, 3391, 4, 6569, 2, 9, 6781, 6747, 4849, 7413, 7, 7339, 9, 2411, 11, 9973, 12, 3535, 2831, 18, 7443, 3773, 9979, 5, 929, 11, 24, 25, 5701