#include <iostream>
#include <cstdlib>
#include <map>
using namespace std;

class key {
	int i;
public:
	key(int initial_i): i(initial_i) {}

	friend bool operator==(const key& key1, const key& key2) {
		return key1.i == key2.i;
	}
};

int main()
{
	map<key, int> m;
	cout << m[key(10)] << "\n";
	return EXIT_SUCCESS;
}