I need help with a ISPICKVAL formula. 

I have a Picklist field named Type_Client_1.  If Type_Client_1= Seller, then the word "Buyer" should display.  If Type_Client_1= Buyer, then the word "Seller" should display. Please help me to correct my formula (see below.

WRONG FORMULA:

if ( ISPICKVAL( ( Type_Contractor_1__c ) , "Seller"), "Buyer",
if ( ISPICKVAL( (Type_Contractor_1__c) , "Buyer")), "Seller"))

Thank you in advance for your time and assistance.

Regards, DNears