class A {
    int i, j;
    A(int a, int b) {
        i = a;
        j = b;
    }
  
    void show() {
        System.out.println("i and j:" + i + " " + j);
    }
}

class B extends A {
    int k;
    B(int a, int b, int c) {
        super(a, b);
        k = c;
    }
  
    void show() {
        System.out.println("k:" + k);
    }
}

class Override {
    public static void main(String args[]) {
        B subOb = new B(1, 2, 3);
        // subOb.show();
        // A yinyong;
        // yinyong=subOb;
        // yinyong.show();
    
        A yinyong;

        yinyong = subOb;
        yinyong.show();
    }
}