class Base
{
int value=0;
Base()
{
addValue();
}
void addValue(){
value+=10;
}
int getValue(){
return value;
}
}
class Derived extends Base
{
Derived()
{
addValue();
}
void addValue(){
value+=20;
}
}
public class one
{
public static void main(
String arg[])
{
Base b=new Derived();
System.out.println(b.getValue());
}
}