#include <iostream>
using namespace std;
 
template<typename T>
auto _test_hello_world_exists(T &f, int) -> decltype(f.helloworld()) {
	cout << "Has Helloworld" << endl;
}
 
template<typename T>
void _test_hello_world_exists(T &f, long) {
	cout << "hasen't helloworld" << endl;
}
 
template<typename T>
void test_hello_world_exists(T &f) {
	_test_hello_world_exists(f, 0);
}
 
class has_helloworld_class {
public:
	void helloworld() {};
};
 
class no_helloworld_class {
};
 
int main() {
	// your code goes here
	has_helloworld_class a;
	no_helloworld_class b;
	test_hello_world_exists(a);
	test_hello_world_exists(b);
	return 0;
}

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