Score : 100 points
Decades have passed since the beginning of AtCoder Beginner Contest.
The contests are labeled as ABC001
, ABC002
, ... from the first round, but after the 999-th round ABC999
, a problem occurred: how the future rounds should be labeled?
In the end, the labels for the rounds from the 1000-th to the 1998-th are decided: ABD001
, ABD002
, ..., ABD999
.
You are given an integer N between 1 and 1998 (inclusive). Print the first three characters of the label of the N-th round of AtCoder Beginner Contest.
Input is given from Standard Input in the following format:
N
Print the first three characters of the label of the N-th round of AtCoder Beginner Contest.
999
ABC
The 999-th round of AtCoder Beginner Contest is labeled as ABC999
.
1000
ABD
The 1000-th round of AtCoder Beginner Contest is labeled as ABD001
.
1481
ABD
The 1481-th round of AtCoder Beginner Contest is labeled as ABD482
.