

void main(){
	
	//auto NM = readLine!long();
	if( readStr() == "ABC" ){
		writeln("ARC");
	} else {
		writeln("ABC");
	}
}



import std;

string readStr(){
	return readln().chomp();
}
T[] readLine( T = long )(){
	return readln().split().to!(T[])();
}