import java.util.*;

public class adivinha {
    public static void main( String[] args ){
        Scanner s = new Scanner(System.in);
        int A = s.nextInt(), B = s.nextInt(), P = s.nextInt();
        s.close();
        int da = Math.abs(A - P), db = Math.abs(B - P);
        if(da < db) System.out.println("A");
        else if(db < da) System.out.println("B");
        else System.out.println("E");
    }
}