#include <bits/stdc++.h>

int main() {
    int a, b;
    scanf("%d%d", &a, &b);
    unsigned int res = 1;
    for (int i = 0; i < 31; i++) {
        if ((a >> i & 1) && !(b >> i & 1)) res = 0;
        if (!(a >> i & 1) && (b >> i & 1)) res *= 2;
    }
    printf("%u\n", (res + 1) >> 1);
    return 0;
}