import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop, core.stdc.stdio;

immutable long MOD = 10^^9 + 7;

void main() {
    auto s = readln.split.map!(to!long);
    auto A = s[0];
    auto B = s[1];

    long ans = 1;
    bool flag = true;

    foreach_reverse (i; 0..35) {
        long a = (A >> i) & 1;
        long b = (B >> i) & 1;
        if (a & b) {

        } else if (a & !b) {
            writeln(0);
            return;
        } else if (!a & b) {
            if (flag) {
                flag = false;
            } else {
                ans = ans * 2;
            }
        } else {

        }
    }

    ans.writeln;
}