Hello Folks,
Below Handler works on Round Robin manner in contact Object. Such that, when Contact record is created , it is assigned to another System Admin, based on Round Robin Manner. It is for 2 users only. What changes should I made so that it could work for multiple users. Please Suggest.

public class RoundRobinContactHandler {
		public static void AssignUser(List<Contact> cn)
        {
            integer countContact = 0;
            String usr;
            List<Contact> cnList = new List<Contact> ();
            
                 
            List<Contact> clist=[Select id, Name, Assigned_To__c from Contact where Assigned_To__r.isActive = TRUE];
            countContact=clist.size();
            integer RnRUserAssigned = Math.mod(countContact, 2) + 1;
            integer CSRindex=0;
            
            if(RnRUserAssigned==1)
            {
                usr=[Select id, name from User where Id = '0052w000002n0Pj' LIMIT 1].id;
            }
            else if (RnRUserAssigned==2)
            {
                usr=[Select id, name from User where Id = '0052w000009deaY' LIMIT 1].id;
            }
            
            if(cn.size()>0 && (usr!=null && usr!='')) 
            {
                for(Contact con : cn)
            	{
                  con.Assigned_To__c= usr;
                 
             	} 
            }
           
         }
}