private Integer getSum(K[] kArray, int index){
		if(index >= kArray.length || kArray[index]==null)
			return 0;
		
		SumTree<K> tempSumTree = new SumTree<K>(kArray[index]);
		
		if(tempSumTree.equals(this)){
			index++;						//looking for next key value
			if(index >= kArray.length){
				return count;				//match all key value, return result
			}else if(kArray[index]==null){
				return 0;					//if next key value is null, then this key doesn't exist
			}else{
				//searching next key value in children
				tempSumTree = new SumTree<K>(kArray[index]);
				int indexOfChildren = children.indexOf(tempSumTree);
				return (indexOfChildren >= 0) ? children.get(indexOfChildren).getSum(kArray, index) : 0;
			}
		}
		return 0;
	}