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)); } // ================================================================== }