#include <iostream>
#include <string>
#include <stdlib.h>

using namespace std;

string s;

int main(void)
{
	cin >> s;
	
	if(s[0] > '0' && s[0] <= '9'){
		int a = atoi(s.c_str()), b;
		if(cin >> b){
			cin >> s;
			cout << a+b << " " << s << endl;
			return 0;
		}
		cout << a*(a+1)/2 << endl;
		return 0;
	}
	
	cout << "Hello World!" << endl;
	return 0;
}