#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
//#define ll __int128
#define int ll
//#define int ll
//#define char ll
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream & operator >> (istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();



signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

#ifdef MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(4) << fixed;
    smain();
#ifdef MAX_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}
const int L = 60;

bool intersects(pll f, pll s) {
    return s.first <= f.second && f.first <= s.second;
}

pll get_union(pll f, pll s) {
    return {min(f.first, s.first), max(f.second, s.first)};
}

void smain() {


    ll l, r;
    cin >> l >> r;
    for (ll x = 0; x < L; ++x) {
        if (((l >> x) & 1) && ((r >> x) & 1) && (r - l + 1) <= (1LL << x)) {
            l ^= 1LL << x;
            r ^= 1LL << x;
        }
    }

    vector<pll> segs = {{l, r}};

    ll st;

    for (ll x = 0; ; ++x) {
        if ((1LL << x) > r) {
            st = x - 1;
            break;
        }
    }
    if (st == -1) {
        cout << r - l + 1;
        return;
    }
    for (int x = 0; x < st; ++x) {
        ll cr = (1LL << x + 1) - 1;
        ll cl = max(l, 1LL << x);
        if (cl > cr)
            continue;
        cr |= 1LL << st;
        cl |= 1LL << st;
        segs.push_back({cl, cr});
    }

    int kek = r - (1LL << st);

    int nst;
    for (ll x = 0; ; ++x) {
        if ((1LL << x) > kek) {
            nst = x - 1;
            break;
        }
    }

    if (nst != -1) {
        segs.push_back({1LL << st, (1LL << st) + (1LL << nst + 1) - 1});
    }

    while (true) {
        int id1 = -1, id2 = -1;
        fori (i, SZ(segs)) {
            fori (j, i) {
                if (intersects(segs[i], segs[j])) {
                    id1 = i;
                    id2 = j;
                }
            }
        }
        if (id1 == -1)
            break;
        vector<pll> nsegs;
        fori (i, SZ(segs)) {
            if (i != id1 && i != id2)
                nsegs.push_back(segs[i]);
        }
        nsegs.push_back(get_union(segs[id1], segs[id2]));
        segs = nsegs;
    }

    ll ans = 0;
    for (auto seg : segs) {
        ans += seg.second - seg.first + 1;
    }
    cout << ans;
}

Measured memory_bytes: 256