a=2017-02-18 23:00:00
a=2017-02-18 23:59:59
a=2017-02-19 00:00:00
a=2017-02-19 00:30:00
a=2017-02-19 01:00:00
a=2017-10-14 23:00:00
a=2017-10-14 23:59:59
a=2017-10-15 00:00:00
a=2017-10-15 00:30:00
a=2017-10-15 01:00:00
