/* package whatever; // don't place package name! */
 
class Ideone {
	public static void main(String[] args) {
 
	}
}
 
interface Builder<B, A> {
  B build(A a);
}
 
class ClientBuilder implements Builder<String, Integer> {
  @Override
  public String build(Integer i) {
    return i.toString();
  }
}
 
abstract class Client<B, A> {
  protected abstract Builder<B, A> getBuilder();
}
 
class ClientClient extends Client<String, Integer> {
 
  @Override
  protected Builder<String, Integer> getBuilder() {
    return null;
  }
}

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