#include <iostream>
using namespace std;
 
class limit {
	int lim;
	int k;
public:
    limit(int lim_, int k_) : lim(lim_), k(k_) {}
    friend ostream& operator<<(ostream& ostr, const limit& lim);
};
 
ostream& operator<<(ostream& ostr, const limit& lim) {
	if (lim.k < lim.lim) {
		ostr << "none";
	} else {
		ostr << lim.k - lim.lim;
	}
	return ostr;
}
 
int main() {
	cout << "Hello " << limit(1, 15) << endl;
	cout << "World " << limit(1, -1) << endl;
	return 0;
}

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