class Solution {
    public String destCity(List<List<String>> paths) {
        Set<String> setA = new HashSet<>(paths.size());
        for(List<String> p : paths){
            setA.add(p.get(0));
        }

        for(List<String> p: paths){
            if(!setA.contains(p.get(1))){
                return p.get(1);
            }
        }

        return "";
    }
}