1obj1.valueOf 2obj1 is 1 3obj1.valueOf 411 5obj2.valueOf 6obj2 is 2 7obj2.valueOf 824 9obj1.valueOf 10obj2.valueOf 113 12obj3.toString 13world12 14obj3.toString 15hello world 16obj1.valueOf 17obj3.toString 181world 19obj2.valueOf 20obj3.toString 212world 22obj3.toString 23obj3.toString 24worldworld 25