import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
public class Main {
  public static void main(String[] args) {
    List<String> names = new ArrayList<>(List.of("Ada", "Lin"));
    names.add("Ada");
    var unique = new HashSet<>(names);
    Map<String, String> mapping = Map.of("recipient", "fullName");
    System.out.println(names.size());
    System.out.println(unique.size());
    System.out.println(mapping.get("recipient"));
  }
}