#include <bits/stdc++.h>

#define pb push_back
#define mp make_pair
#define sz size
#define ll long long
#define ld long double
#define fs first
#define sc second
#define forn(i, f, t) for(int i = f; i < t; i++)
#define all(x) (x).begin(), (x).end()
#define ins insert

const int INF = 2147483647;
const int MOD = 1000000007;
const ll INF64 = 9223372036854775807;
const ld EPS = 1e-7;

using namespace std;


int main(){
    int l, r;
    scanf("%d%d", &l, &r);
    int n = r - l + 1;

    r++;

    int k = 0, cntl[31];
    while ((1 << k) <= l) k++; k--;
    forn(i, 0, 31) cntl[i] = 0;
    vector<int> posl;
    while (l){
        if (l & (1 << k)){
            forn(i, 0, k) cntl[i] += (1 << (k - 1));
            forn(i, 0, posl.sz()) cntl[posl[i]] += (1 << k);
            posl.pb(k);
            l ^= (1 << k);
        }
        k--;
    }
    // forn(i, 0, 16) printf("%d ", cntl[i]); printf("\n");

    k = 0;
    int cntr[31];
    while ((1 << k) <= r) k++; k--;
    forn(i, 0, 31) cntr[i] = 0;
    vector<int> posr;
    while (r){
        if (r & (1 << k)){
            forn(i, 0, k) cntr[i] += (1 << (k - 1));
            forn(i, 0, posr.sz()) cntr[posr[i]] += (1 << k);
            posr.pb(k);
            r ^= (1 << k);
        }
        k--;
    }
    // forn(i, 0, 16) printf("%d ", cntr[i]); printf("\n");

    int cnt[31];
    forn(i, 0, 31)
        cnt[i] = cntr[i] - cntl[i];
    // forn(i, 0, 16) printf("%d ", cnt[i]); printf("\n");
    ll ans = 0ll;
    forn(i, 0, 31) if (cnt[i] * 2 > n) ans += (1 << i);
    cout << ans << "\n";
    return 0;
}