State Validation Rule

The US State contains 2 Letters. 

1. Create a Text field and the set values as "2"

2. To write a below validation rule  

OR( ISNUMBER( State__c ), OR(CONTAINS(State__c , "!"),CONTAINS(State__c , "@"),CONTAINS(State__c , "#"),CONTAINS(State__c , "$"),CONTAINS(State__c , "$"),CONTAINS(State__c , "%"),CONTAINS(State__c , "^"),CONTAINS(State__c , "&"),CONTAINS(State__c , "*")))