import java.util.Map;
import java.util.HashMap;

public class Task051125 {
    public static void main(String[] args) {
        Map<String, Integer> map = new HashMap<>();
        map.put("a", 1);
        map.put("b", 2);
        map.put("c", null);
        
        Integer value1 = map.get("a");
        Integer value2 = map.get("c");
        Integer value3 = map.get("d");
        int value4 = map.getOrDefault("d", -1);
        
        System.out.println(value1);
        System.out.println(value2);
        System.out.println(value3);
        System.out.println(value4);
    }
}