Polymorphism and Method Overriding

What is printed as a result of executing the following program?

class A {
    public String fun() { return "A"; }
    public String fun(String s) { return s + "A"; }
}

class B extends A {
    public String fun() { return "B"; }
    public String fun(String s) { return s + fun(); }
}

public class Main {
    public static void main(String[] args) {
         A obj = new B();
         System.out.println(obj.fun("Start"));
    }
}