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: ['2849', '6949', '5823', '7801', '9213', '1481', 'z', 'f', '6307', 'L', '2143', 'm', 'P', '2385', 'U', '2939', 'D', '3763', 'l', '6107']

2849, 6949, 5823, 7801, 9213, 1481, 26, 6, 6307, 12, 2143, 13, 16, 2385, 21, 2939, 4, 3763, 12, 6107