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Score : $200$ points

### 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:

$S_1$
$S_2$
$S_3$


### 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