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: ['1915', '7871', 'L', '7433', '1833', 'D', 'U', '7269', '4945', 'f', '1371', '9477', 'e', '8317', 'S', 'x', '6649', 'S', 'c', '9339', '4785', '5933', 'E', 'V', 'Y', 'G', '8055', 't', 'l', '271', '4493', '5155']

1915, 7871, 12, 7433, 1833, 4, 21, 7269, 4945, 6, 1371, 9477, 5, 8317, 19, 24, 6649, 19, 3, 9339, 4785, 5933, 5, 22, 25, 7, 8055, 20, 12, 271, 4493, 5155