I am looking for a help to write a Formula in the following scenario

Suppose In Cell A1 & A2 two numbers are there.
I want to show a message in Cell A3, Say "Err" if the difference is higher than 1 and lower than -1
If I need only to make one condition, say, higher than 1, I can write the formula as given below
=if((A1-A2)>1,"Err","").
But I need to integrate second condition. I request the members who know the solution, publish an answer.
Best Regards
Dominic