#include <iostream>

using fun = int(*)(int, int);

int main() {
	fun f1 = +[](int a, int b) { return a + b; };
	fun f2 = static_cast<fun>([](int a, int b) { return a + b; });

	std::cout << f1(1, 2) << std::endl;
	std::cout << f2(2, 3) << std::endl;
	
	return 0;
}