100990: [AtCoder]ABC099 A - ABD
Description
Score : $100$ points
Problem Statement
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.
Constraints
- $1 \leq N \leq 1998$
- $N$ is an integer.
Input
Input is given from Standard Input in the following format:
$N$
Output
Print the first three characters of the label of the $N$-th round of AtCoder Beginner Contest.
Sample Input 1
999
Sample Output 1
ABC
The $999$-th round of AtCoder Beginner Contest is labeled as ABC999
.
Sample Input 2
1000
Sample Output 2
ABD
The $1000$-th round of AtCoder Beginner Contest is labeled as ABD001
.
Sample Input 3
1481
Sample Output 3
ABD
The $1481$-th round of AtCoder Beginner Contest is labeled as ABD482
.