#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int,int> P;

#define p_ary(ary,a,b) do { cout << "["; for (int count = (a);count < (b);++count) cout << ary[count] << ((b)-1 == count ? "" : ", "); cout << "]\n"; } while(0)
#define p_map(map,it) do {cout << "{";for (auto (it) = map.begin();;++(it)) {if ((it) == map.end()) {cout << "}\n";break;}else cout << "" << (it)->first << "=>" << (it)->second << ", ";}}while(0)

int main() {
    int a,b;
    cin >> a >> b;
    int cnt = 0;
    bool ok = true;
    for (int i = 0;i < 31;++i) {
        if (((a>>i)&1) == 0 && ((b>>i)&1)) cnt++;
        if (((a>>i)&1) && ((b>>i)&1) == 0) ok = false;
    }
    if (ok) {
        if (cnt) cnt--;
        cout << (1<<cnt) << endl;
    } else {
        cout << 0 << endl;
    }
}