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: ['6677', '3955', 'R', 'Q', '3603', 'd', 'm', 'X', 't', 'y', 'Z', 'S', 't', 'Z', '5873', '7309', 'H']

6677, 3955, 18, 17, 3603, 4, 13, 24, 20, 25, 26, 19, 20, 26, 5873, 7309, 8