Merging map a with b into c how to do ?

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

class Solution {


    public static void main(String[] args)
    {

        Map<Integer, String> myFavoriteColours = new HashMap<>();
        Map<Integer, String> myFriendsFavoriteColours = new HashMap<>();

        myFavoriteColours.put(1, "Purple");
        myFavoriteColours.put(2, "Yellow");
        myFavoriteColours.put(3, "Black");
        System.out.println("Values in first map: " + myFavoriteColours);
        myFriendsFavoriteColours.put(4, "White");
        myFriendsFavoriteColours.put(5, "Silver");
        myFriendsFavoriteColours.put(6, "Orange");
        System.out.println("Values in second map: " + myFriendsFavoriteColours);

        Map<Object, Object> ourFavoriteColours = new HashMap<>();
        ourFavoriteColours.put(myFavoriteColours);
        ourFavoriteColours.put(myFriendsFavoriteColours);
        System.out.println("Values in third map: " + ourFavoriteColours);
    }
}