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: ['c', '7881', 'U', '9213', 'L', '1457', '3139', '7433', '5967', '2663', 'c', '6649', 'q', '5545', 'w', '1747', 'Y', 'z', '6429', '7749', 'U', '815', 'u', '1381', 'd', '6467', '3213', '6939', 'w', '8041', 'o', 'b', 'Z', 'd']

3, 7881, 21, 9213, 12, 1457, 3139, 7433, 5967, 2663, 3, 6649, 17, 5545, 23, 1747, 25, 26, 6429, 7749, 21, 815, 21, 1381, 4, 6467, 3213, 6939, 23, 8041, 15, 2, 26, 4