import java.io.InputStream;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.Stack;
import java.util.TreeSet;

import static java.util.Comparator.*;

public class Main {
    public static void main(String[] args) {
        PrintWriter out = new PrintWriter(System.out);
        Solver solver = new Solver(System.in, out);
        solver.solve();
        out.close();
    }
}
class Solver {
	Scanner sc;
	PrintWriter out;
    public Solver(InputStream in, PrintWriter out) {
    	sc = new Scanner(in);
    	this.out = out;
    }
    // ==================================================================
    public void solve() {
    	int A = Integer.parseInt(sc.next());
    	int B = Integer.parseInt(sc.next());
    	if(A > B) {
    		out.println(0);
    		return;
    	}
    	char[] ca = Integer.toBinaryString(A).toCharArray();
    	char[] cb = Integer.toBinaryString(B).toCharArray();
    	int offset = cb.length - ca.length;
    	if(ca[0] != cb[offset]) {
    		out.println(0);
    		return;
    	}
    	int cnt = 1, flg = 0;
    	if(offset > 0)	flg = 1;
    	for (int i = 1; i < ca.length; i++) {
    		if(ca[i] == 1 && cb[i+offset] == 0) {
        		out.println(0);
        		return;
    		}
			if(flg == 0 && ca[i] != cb[i+offset]) {
				flg = 1;
			} else if(ca[i] != cb[i+offset]) {
				cnt *= 2;
			}
		}
    	out.println(cnt);
    }
    // ==================================================================
}