The housekeeping department of a hotel has two four-story buildings, A and B, each with 20 rooms. Please code the hotel room.

You can use the letter A or B to indicate which building it is, then use the four numbers 1 ~ 4 in the second place to indicate which floor it is, and the last two digits use 0 1 ~ 20 to indicate which room it is;

For example, building A/floor 0/0 of KLOC-0/9 can be numbered as A 10 19.