interface Data1 {
    int a = 1;   
    int b = 2;   
    int calc1(); 
    int calc2(); 
}

interface Data2 extends Data1 {
    int c = 3;
    int calc3();
}

interface Data3 {
    int d = 4;
    int calc4();
}

class DataA implements Data1 {
    public int calc1() { return a; }
    public int calc2() { return b; }
}

class DataB extends DataA implements Data2, Data3 {
    public int calc3() { return c; }
    public int calc4() { return d; }
}

public class InterfaceFun {
    public static void main(String[] args) {
	DataB x = new DataB();
	System.out.println(x.calc1()+""+x.calc2()+""+
			   x.calc3()+""+x.calc4());
	
    }
}

// output: 1234