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

import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		List<Integer> ints = new ArrayList<Integer>(); 
		List<Double> doubles = new ArrayList<Double>(); 
		check(null);
		check(ints);
		ints.add(1);
		check(ints);
		doubles.add(1D);
		check(doubles);
	}
	
	public static void check(List<?> list) {
		if (Objects.equals(null, list)) 
			System.out.println("null");
		else if (list.isEmpty())
			System.out.println("empty");
		else if (list.get(0) instanceof Integer)
			System.out.println("int");
		else if (list.get(0) instanceof Double)
			System.out.println("double");
	}
}