import java.util.*;
class A<T> {
}
class B<S> extends A {
}
class C extends A {
}
class D extends A {
}
public class Main {
public static void test(Collection extends A> c) {}
public static void main(String[] args) {
Collection bs = new ArrayList();
test(bs);
Collection cs = new ArrayList();
test(cs);
Collection ds = new ArrayList();
test(ds);
}
}