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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<stack>
#include<vector>
#include<map>
#include<queue>
#include<cmath>
#include<set>
#include<cstdlib>
#include<cctype>
#include<ctime>
#include<utility>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const ll maxn = 1e5 + 5;
const ll maxm = 1e3 + 5;
template<class T>
inline T qread(T &IEE){
	register T x = 0, f = 1;
	register char ch = getchar();
	while(!isdigit(ch)){
		if(ch == '-'){
			f = -f;
		}
		ch = getchar();
	}
	while(isdigit(ch)){
		x = (x << 1) + (x << 3) + (ch ^ 48);
		ch = getchar();
	}
	return IEE = x * f;
}
template<class T>
inline void qwrite(T a){
	if(!a){
		putchar('0');
		return ;
	}
 	if(a < 0){
		putchar('-');
		a = -a;
	}
	if(a > 9) qwrite(a / 10);
	putchar(a % 10 + 48);
	return ;
}
string s;
int main(){
//	freopen("1.in", "r", stdin);
//	freopen("1.out", "w", stdout);
	cin >> s;
	if(s == "ABC"){
		puts("ARC");
	} else {
		puts("ABC");
	}
	return 0;
}