I got system.limit exception:Apex CPU Time limit exceeded for my trigger .Please let me know which one need to improve to avoid that error. The error report at line 22,column 1

trigger LineItemTypeTrigger on Line_Item_Type__c (after update) {
    try
    {
        if (Trigger.isUpdate && Trigger.isAfter)
        {
            Map<String, Decimal> oldRecAuditAmount = new Map<String, Decimal>();
            Map<String, Decimal> oldRecAmount = new Map<String, Decimal>();
            Set<String> litTriggerIds = new Set<String>();
            for (Line_Item_Type__c oldRec : Trigger.old) {
                if (oldRec.Calculated_Amount__c != null)
                    oldRecAmount.put(oldRec.Id, oldRec.Calculated_Amount__c );
                if (oldRec.Calculated_Audit_Amount__c != null)
                    oldRecAuditAmount.put(oldRec.Id, oldRec.Calculated_Audit_Amount__c );
            }
            
            for (Line_Item_Type__c newRec : Trigger.new) {
                if (oldRecAmount.containsKey(newRec.Id))
                    if (oldRecAmount.get(newRec.Id) != newRec.Calculated_Amount__c )
                        litTriggerIds.add(newRec.Id);
                if (oldRecAuditAmount.containsKey(newRec.Id))
                    if (oldRecAuditAmount.get(newRec.Id) != newRec.Calculated_Audit_Amount__c )
                        litTriggerIds.add(newRec.Id);
            }
            
            if (litTriggerIds.size() > 0)
            {
                LineItemTypeTriggerHandler handler = new LineItemTypeTriggerHandler();  
                handler.OnAfterUpdate(litTriggerIds);
            }
        }
    }
    catch (Exception e)
    {
        System.debug('Error Occurred:' + '[' + e.getMessage() +' ]');
    }
}