import java.util.*;

class Main {
  public static void main(String[] args) {
    System.out.println("hello world");
    System.out.println(drawTriangle(5));
    hashTweets("dahvfkl vsjlkh dshdl #slbns @bsnjklvn vndfi#vfdvns");
  }
  public static String drawTriangle(int sizetri){
 	String tri = "";
 	for(int i =0; i <= sizetri; i++){
 		tri += "\n";
 		for(int j =0; j < i; j++){
 			tri += "#";
 		}
 	}
 	return tri;
 }

 public static void hashTweets(String tweet){
 	String[] tweetlist = tweet.split(" ");
 	List<String> hashMentions = new ArrayList<String>();
 	for (int i = 0; i < tweetlist.length; i++){
 			boolean isHash = (tweetlist[i].charAt(0) == '#');
 			boolean isMention =(tweetlist[i].charAt(0) == '@');
 			if (isHash || isMention){
 				hashMentions.add(tweetlist[i]);
 		}
 	}
	System.out.println(hashMentions);
 }

}