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: ['R', '8615', 'R', '3327', 'm', 'l', 'b', 'n', '6099', 'l', 'd', 'M', '9149', 'Y', '6259', 'X', '1495', '7697', 'u', '7783', '5007', 'a', '2865', 'n', 'C', '3609', '2995', '9065', '1233', '7115']

18, 8615, 18, 3327, 13, 12, 2, 14, 6099, 12, 4, 13, 9149, 25, 6259, 24, 1495, 7697, 21, 7783, 5007, 1, 2865, 14, 3, 3609, 2995, 9065, 1233, 7115