Time expression help

[Pratyay_Rakshit]

I need to formulate

if( time > 12 PM, use “[time]&AM”, use"[Time]-12"&PM)

I’m using this:

if(
[Start Time]-12:00>0, concatenate([Start Time], " AM"), concatenate(([Start Time]-12), " PM"))

I’m being shown:

Arithmetic expression ‘(([Start Time]-“12:00”) > 0)’ does not have valid input types

What exactly do I have to change here?