import java.util.*;

class Day {
	private int y,m,d;
	public Day(int y1,int m1,int d1) {y=y1;m=m1;d=d1;}
	public String toString() {return d+"/"+m+"/"+y;}
	@Override public int hashCode() { return y*10000+m*100+d; }
	@Override public boolean equals(Object x) {return y*10000+m*100+d==((Day)x).y*10000+((Day)x).m*100+((Day)x).d;}
}

class Main {
	public static void main(String[] args) {
		Map<Day, Integer> m = new HashMap<>();
		m.put(new Day(2015, 4, 15), 100);
		m.put(new Day(2012, 12, 31), 200);
		m.put(new Day(2015, 4, 15), 1100);
		Set<Day> kSet = m.keySet();
		for (Day k : kSet)
			System.out.printf("%s(%d)\n", k, m.get(k));
	}
}


/*
HashMap only:
31/12/2012(200)
15/4/2015(100)
15/4/2015(1100)
*/

/*
HashMap + equals:
31/12/2012(200)
15/4/2015(100)
15/4/2015(1100)
*/

/*
HashMap + hashCode:
15/4/2015(1100)
15/4/2015(100)
31/12/2012(200)
*/

/*
HashMap + hashCode + equals:
15/4/2015(1100)
31/12/2012(200)
*/