class A {
    public int foo () { return 0; }
}

class B: A{
    public int foo () { return 1; }
    public int bar() { return 0;}
}

int main (){
    A a = new B();
    printf("a.foo() = %d\n", a.foo());
    printf("a.bar() = %d\n", a.bar());
    return 0;
}