Score : $200$ points

问题描述

AtCoder 目前举办了四个系列的常规比赛：ABC、ARC、AGC 和 AHC。

除了 $S_1$、$S_2$ 和 $S_3$ 之外，AtCoder 目前还举办哪个系列的常规比赛？

以上为通义千问 qwen-max 翻译，仅供参考。

Problem Statement

AtCoder currently holds four series of regular contests: ABC, ARC, AGC, and AHC.

What is the series of regular contests currently held by AtCoder in addition to $S_1$, $S_2$, and $S_3$?

Constraints

• Each of $S_1$, $S_2$, and $S_3$ is ABC, ARC, AGC, or AHC.
• $S_1$, $S_2$, and $S_3$ are pairwise different.

Input

Input is given from Standard Input in the following format:

$S_1$

$S_2$

$S_3$

Output

Print the answer.

Sample Input 1

ARC
AGC
AHC

Sample Output 1

ABC

Given in input are ARC, AGC, and AHC. The rest is ABC.

Sample Input 2

AGC
ABC
ARC

Sample Output 2

AHC

update @ 2024/3/10 09:36:29