有如下类声明：
class Base{
protected;
int amount;
public;
Base(int n=0):amount(n){}
int getAmount()const{return amount;}
};
class Derived:public Base{
protected;
int value;
public;
Derived(int m,int n):value(m).Base(n){}
Int getData()const{return value+amount;}
};
己知x是一个Derived对象，则下列表达式中正确的是______。