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

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		List<String[]> arrays = new LinkedList<String[]>();
                arrays.add(new String[]{"a", "b", "c"});
                arrays.add(new String[]{"d", "e", "f", "g"});
                
                String[][] matrix = arrays.toArray(new String[0][]);

                for (String[] s:matrix)
                  System.out.println(Arrays.toString(s));
	}
}