#include <iostream>
using namespace std;

#define func1(x, y) ((x + y) * (x - y))

inline int func2(int x, int y) {
	return (x - y) * (x + y);
}

int func3(int x, int y) {
	return func1(x, y);
}
 
int main() {
	
	cout << func1(5, 4) << endl;

	cout << func2(5, 4) << endl;
	
	cout << func3(5, 4) << endl;
	
	return 0;
}