Exception in thread "main" java.lang.IllegalStateException [com.javarush.task.task08.task0819.Solution$Cat@74a14482, com.javarush.task.task08.task0819.Solution$Cat@4554617c, com.javarush.task.task08.task0819.Solution$Cat@1540e19d] at java.util.HashMap$HashIterator.remove(HashMap.java:1449) at com.javarush.task.task08.task0819.Solution.main(Solution.java:17)