import java.util.*;
import java.lang.*;

class Main {
    public static void main(String[] args) {
        Map<String,Integer> phone = new HashMap<>();
        phone.put("Barack Obama", 111111);
        phone.put("Donald Trump", 222222);
        phone.put("Joe Biden", 3333333);
        
        System.out.println(phone.size());
        System.out.println(phone.containsKey("Barack Obama"));
        System.out.println(phone.containsKey("Donald Trump"));
        
        System.out.println(phone.get("Barack Obama"));
        System.out.println(phone.get("Bill Clinton"));
        
        // using keySet()
        for (String s: phone.keySet()) {
            Integer value = phone.get(s);
            System.out.println(s + " -> " + value);
        }
        System.out.println("####");
        
        // using values()
        System.out.println(phone.values());
        System.out.println("####");
        
        // using entrySet()
        for (Map.Entry<String, Integer> e: phone.entrySet()) {
            String key = e.getKey();
            Integer value = e.getValue();
            System.out.println(key + " -> " + value);
        }
        System.out.println("####");
        
        // using stream api
        phone.entrySet()
            .stream()
            .filter(x -> !x.getKey().contains("B"))
            .map(x -> x.getValue())
            .forEach(System.out::println);
    }
}