Problem:
Score : 100 points

Problem Statement

AtCoder Inc. holds a contest every Saturday.

There are two types of contests called ABC and ARC, and just one of them is held at a time.

The company holds these two types of contests alternately: an ARC follows an ABC and vice versa.

Given a string S representing the type of the contest held last week, print the string representing the type of the contest held this week.

Constraints

S is ABC or ARC.

Input

Input is given from Standard Input in the following format:

S

Output

Print the string representing the type of the contest held this week.

Sample Input 1

ABC

Sample Output 1

ARC

They held an ABC last week, so they will hold an ARC this week.

Solution in C (GCC 9.2.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
int main(void)
{
	int i,len,flg;
	char s[3];
	scanf("%s",s);
	len=strlen(s);
	flg=0;
	for(i=1;i<=len;i++){
		if(s[1]=='B'){
			flg=1;
		}
		else{
			flg=0;
		}
	}
	if(flg==1){
		printf("ARC\n");
	}
	else{
		printf("ABC\n");
	}
	return 0;
}