#include <iostream>
#include <cstring>
#include <algorithm>
#define int long long
const int N = 1e9+10;
const int NN = 2e4+10;
using namespace std;
int qmi(int a, int k)
{
    int res = 1;
    while (k)
    {
        if (k & 1) res = res * a;
        a = a * a;
        k >>= 1;
    }
    return res;
}
int a[NN],cnt,la;
int get_1(int n){
    int re = 0;
    while (n){
        if (n % 2 == 1){
            re ++;
        }
        n /= 2;
    }
    return re;
}
void init()
{
    int j = -1;
    while (la <= N){
        j += 2;
        a[cnt++] = j << get_1(j);
        la = a[cnt-1];
    }
    sort(a,a + cnt);
}
signed main(){
    init();
    //cout << NN << ' ' << cnt << '\n';
    //for (int i = 0; i < cnt; i ++ )cout << a[i] << " ";
    int q;
    cin >> q;
    while (q -- ){
        int l,r;
        cin >> l >> r;
        int ll = 0, rr = cnt, mid;
        while(1){
            mid = (ll + rr) / 2;
            if(a[mid] < l) ll = mid+1;
            if(a[mid] > r) rr = mid;
            if(a[mid] >= l && a[mid] <= r) break;
            if(a[mid-1] <= l && a[mid] >= r) break;
        }
        if(a[mid] > r )cout << -1 <<'\n';
        else cout << a[mid] << '\n';
    }
}