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

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		List<?> j = null;
        List<Integer> j2 = (List<Integer>)j;
        
        List<List<?>> i = null;
        List<List<Integer>> i2 = (List<List<Integer>>) (List<?>) i;
	}
}