#nullable enable

#region
var (_input, _iter) = (Array.Empty<string>(), 0);
T I<T>() where T : IParsable<T>
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Trim().Split(' '), 0);
    return T.Parse(_input[_iter++], null);
}
#endregion

var ans = new List<long>();
var t = I<int>();
while (t-- > 0)
{
    var l = I<long>();
    var r = I<long>();
    if (r == 0)
    {
        ans.Add(0);
        continue;
    }
    for (var i = 32; i >= 0; i--)
    {
        var b = 1L << i;
        if ((r & b) == 0) continue;
        if ((l & b) != 0)
        {
            ans.Add(-1);
        }
        else
        {
            ans.Add(b * (b - 1));
        }
        break;
    }
}
Console.WriteLine(string.Join(Environment.NewLine, ans));