写出以下标出行号的语句的执行顺序。abstractclassP{publicP(){System.out.print("parent");//3}abstractvoidm();}classSextendsP{publicS(){System.out.print("child");//2}publicstaticvoidmain(Stringa[]){Px=newS();x.m();}voidm(){System.out.print("m()");//1}}请连续书写数字,中间不留任何符号,如123