Is there a way for Excel to return the output of a formula that is itself being used as the IF criteria?

For example, I want to work with a formula that let's say rounds up the output of a formula to a whole number, and if the result is a positive number, then I want the output of that very formula i.e. the rounded whole number output of the nested formula. As below:

=IF(ROUND(IF(LEFT(A1,3)="ABC",B1+C1,0))>0,ROUND(IF(LEFT(A1,3)="ABC",B1+C1,0),"")

Thanks!

(Any other tips to simplify it in any other way is really really welcome too : ))