class Commercial {
int i=0;
Commercial(int a) {
i = a;
}
void calculateBill() {
int units=100;
int cost=100*i;
System.out.println("Commercial Bill is of Rs "+cost);
}
}

class Domestic extends Commercial {
int k=0;
Domestic(int a, int b) {
super(a);
k = b;
}
void calculateBill() {
int units=100;
int cost=100*k;
super.calculateBill();
System.out.println("Domestic Bill is of Rs "+cost);
}
}

class Bill {
public static void main(String args[]) {
Domestic bill = new Domestic(8, 6);
bill.calculateBill(); 
}
}