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() {
    	long A = Long.parseLong(sc.next());
    	long B = Long.parseLong(sc.next());
    	if(A > B) {
    		out.println(0);
    		return;
    	}
    	int cnt = 0;
    	for (int i = 32; i >= 0; i--) {
			if((B & (1L << i)) != 0) {
				if((A & (1L << i)) == 0) {
					cnt++;
				}
			} else {
				if((A & (1L << i)) != 0) {
					out.println(0);
					return;
				}
			}
		}
    	out.println(1L << (cnt - 1));
    }
    // ==================================================================
}