/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
//	@FunctionalInterface
	public interface MyLambda {
		public default int hashCode() {
			return 0;
		}
		String message();
	}
	
	public static void main (String[] args) throws java.lang.Exception
	{
		HashSet<MyLambda> set = new HashSet<>();
		set.add(() -> "Greg");
		set.add(() -> "Mark");
		
		System.out.println(set.size());
	}
}