#include <cstdio>
#include <iostream>
using namespace std;
int T;
long long l, r;
int main() {
    scanf("%d", &T);
    while (T--) {
        scanf("%lld%lld", &l, &r);
        long long ans = -1, val = 0ll;
        int cnt = 0;
        for (int i = 32; ~i && !(~ans); i--) {
            if (!((l >> i & 1) ^ (r >> i & 1))) cnt += (l >> i & 1), val |= (l & (1ll << i));
            else if ((r >> i & 1) && !(l >> i & 1)) {
                long long tmp = val | (1ll << i);
                if (cnt + 1 == i) {
                    if (tmp <= r) ans = tmp;
                } else if (cnt + 2 < i) {
                    tmp |= (1ll << cnt + 2);
                    if (tmp <= r) ans = tmp;
                }
            }
        }
        printf("%lld\n", ans);
    }
    return 0;
}