$start1 = Carbon::createFromFormat('Y-m-d', '2018-12-01');
$end1 = Carbon::createFromFormat('Y-m-d', '2019-03-15');
$start2 = Carbon::createFromFormat('Y-m-d', '2019-05-06');
$end2 = Carbon::createFromFormat('Y-m-d', '2019-10-10');