public static String gameOfThrones(String str) {
    Map<String, Long> charcount = Arrays.
    stream(str.split("")).
    collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

    long count = charcount.entrySet().stream().filter(en -> en.getValue() % 2 != 0).count();

    return count==0 || count==1 ? "YES" : "NO";

}