How can I write "or" in c# script

Hello sir, I'm a newbie and sorry if this is a stupid question.

Code (CSharp):

1. if (other.gameObject.tag != ("StealthKillA") ("StealthKillB")("StealthKillC")("StealthKillD")) return;

This code is error no doubt, as you can see I got 4 tags with a similar idea and I try to write it into c# script. How do I tell in c# that "if tag not equal to StealthKillA or StealthKillB or StealthKillC or StealthKillD" ... return;

For now, I solve this by writing the hold thing again 4 times (Stupid I know) but how to write it correctly?

 

Or better yet: http://learncs.org/

 

You actually probably want 'and' for this one, not or. Boolean logic doesn't quite work the same way as spoken logic.

Code (CSharp):

1. if (other.gameObject.tag != ("StealthKillA")
2.     && other.gameObject.tag != ("StealthKillB")
3.     && other.gameObject.tag != ("StealthKillC")
4.     && other.gameObject.tag != ("StealthKillD")) return;

 

Thank you, sir. This helped me a lot.