import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Scanner;

class Main {

	public static void main(String[] args) {
		new Main().run();
	}
	
	void run() {
		Scanner sc = new Scanner(System.in);
		int n=sc.nextInt();
		int[] C=new int[n];
		int c1=0,c2=0,c=0;
		for(int i=0;i<n;++i) {
			C[i]=sc.nextInt();
			if(C[i]==1)++c1;
			else if(C[i]==2)++c2;
			else c+=C[i];
		}
		if(((c+c2)==0&&c1%2==1)||(c==0&&c2==1&&(c1+2*c2)%2==1)) {
			System.out.println("A");
		}else{
			System.out.println("B");
		}
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
}