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: ['6393', 'r', '6639', '5477', '5313', '5767', '977', '1673', 'J', 'M', 'u', 'H', 'p', '2555', 'm', '469', '6965', 'A', 'f', 'v', '7453', 'h', 'c', 'p', 'i', '3971', '841', '4559', 'l', '6859']

6393, 18, 6639, 5477, 5313, 5767, 977, 1673, 10, 13, 21, 8, 16, 2555, 13, 469, 6965, 1, 6, 22, 7453, 8, 3, 16, 9, 3971, 841, 4559, 12, 6859