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: ['7921', 'M', '1819', '3491', 'e', '2909', 'V', '6719', 'D', 'C', 'P', 'w', '3907', 'S', 'A', '4795', 'Y', 't', 'i']

7921, 13, 1819, 3491, 5, 2909, 22, 6719, 4, 3, 16, 23, 3907, 19, 1, 4795, 25, 20, 9