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 Rust (1.15.1) (judge verdict: Accepted)

fn main () {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).unwrap();
    match n.trim() {
        "1" => a(),
        "2" => b(),
        _ => panic!(),
    }
}

fn a () {
    println!("Hello World");
}

fn b () {
    let mut a = String::new();
    let mut b = String::new();
    std::io::stdin().read_line(&mut a).unwrap();
    std::io::stdin().read_line(&mut b).unwrap();
    println!("{}", a.trim().parse::<usize>().unwrap() + b.trim().parse::<usize>().unwrap());
}