#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

void solve()
{
  int l, r;
  cin >> l >> r;
  int v = -1;
  for (int i = 1 << 30; i > 0; i >>= 1)
  {
    if (l < i && i <= r)
    {
      v = i;
      break;
    }
  }
  if (v == -1)
  {
    cout << "-1\n";
    return;
  }
  long long ans = (long long)v * (v - 1);
  cout << ans << endl;
}

int main()
{
  int t;
  cin >> t;
  while (t--) solve();
}