Problem:
﻿Score: 100 points

Problem Statement

In 2020, AtCoder Inc. with an annual sales of more than one billion yen (the currency of Japan) has started a business in programming education.

One day, there was an exam where a one-year-old child must write a program that prints Hello World, and a two-year-old child must write a program that receives integers A, B and prints A+B.

Takahashi, who is taking this exam, suddenly forgets his age.

He decides to write a program that first receives his age N (1 or 2) as input, then prints Hello World if N=1, and additionally receives integers A, B and prints A+B if N=2.

Write this program for him.

Constraints

N is 1 or 2.

A is an integer between 1 and 9 (inclusive).

B is an integer between 1 and 9 (inclusive).

Input

Input is given from Standard Input in one of the following formats:

1

2
A
B

Output

If N=1, print Hello World; if N=2, print A+B.

Sample Input 1

1

Sample Output 1

Hello World

As N=1, Takahashi is one year old. Thus, we should print Hello World.

Sample Input 2

2
3
5

Sample Output 2

8

As N=2, Takahashi is two years old. Thus, we should print A+B, which is 8 since A=3 and B=5.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Main {
	private static BufferedReader br = null;
	
	public static void main(String[] args) {
		int n = Integer.parseInt(read(1)[0]);
		
		if (n == 1) {
			System.out.println("Hello World");
		} else {
			String[] strs = read(2);
			System.out.println(Integer.parseInt(strs[0]) + Integer.parseInt(strs[1]));
		}
	}
	
	private static String[] read(int len) {
		List<String> strList = new ArrayList<>();
		
		try {
			if (br == null) {
				br = new BufferedReader(new InputStreamReader(System.in));
			}
			
			for (int i = 0; i < len; i++) {
				strList.add(br.readLine());
			}
		} catch (IOException e) {
		}
		
		return strList.toArray(new String[0]);
	}
	
	private static void close() {
		try {
			if (br != null) {
				br.close();
			}
		} catch (IOException e) {
		}
	}
}