unittest
{
	assert( [ "1" ].parse.expand.solve == "Hello World" );
	assert( [ "2", "3", "5" ].parse.expand.solve == "8" );
}



import std.conv;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

void main()
{
	stdin.byLineCopy.parse.expand.solve.writeln;
}

auto parse( Range )( Range input )
if( isInputRange!Range && is( ElementType!Range == string ) )
{
	auto n = input.front.strip.to!( long );
	auto a = 0L;
	auto b = 0L;
	if( n == 2 )
	{
		input.popFront;
		a = input.front.strip.to!( long );
		input.popFront;
		b = input.front.strip.to!( long );
	}
	return tuple( n, a, b );
}

auto solve( long n, long a, long b )
{
	if( n == 1 ) return "Hello World";
	else         return ( a + b ).to!string;
}
