Insert all data values in the linked list
head = push ( head , 5 ) ; head = push ( head , 21 ) ; head = push ( head , 8 ) ; head = push ( head , 12 ) ; head = push ( head , 3 ) ; head = push ( head , 13 ) ; head = push ( head , 144 ) ; head = push ( head , 6 ) ; document . write ( meanofnodes ( head ) ) ;