how to subtract the datetimes

I have cell values that are in datetimes :

a= {[12/09/2022 04:28:01 PM]}

and

b={[12/09/2022 04:28:26 PM]}.

I want to subtract both datetimes to get the difference. I am trying it with code :

datetime(a, 'InputFormat', 'mm/dd/yyyy HH:MM:SS PM');

but it is not working.

Answer 1

[Stephen23]

ac = {'12/09/2022 04:28:01 PM'};
bc = {'12/09/2022 04:28:26 PM'};
at = datetime(ac, 'InputFormat','M/d/y h:m:s a')

at = datetime
   09-Dec-2022 16:28:01

bt = datetime(bc, 'InputFormat','M/d/y h:m:s a')

bt = datetime
   09-Dec-2022 16:28:26

bt-at

ans = duration
   00:00:25

[MakM]

Thanks Stephan for the help.