import java.util.*;

/*
		t1 t2 t3 ....... tn

		1   1  1
		2   2  2
		3      3
		       4

n is variable . And number of elements in each ti are also variable.
output should be all combinations of elements taken from each ti at a time

e.g output

		1  1  1
        1  1  2
		1  1  3
		1  1  4
		1  2  1
		1  2  2
		1  2  3
		1  2  4
		2  1  1
		2  1  2 ... and so on

*/

// problem defn:  size of T is variable. and the vectors present in T are also of variable sizes
public class TestingRecurse
{

public Vector t; // T is a vector of vectors
public Vector parcel; // a vector of Strings


public static void main(String args[])
{
	TestingRecurse tr = new TestingRecurse();

	tr.t = new Vector();

	Vector temp; // a vector of Strings

	String a = new String("a");
	String b = new String("b");
	String c = new String("c");
	String d = new String("d");
	String e = new String("e");

	temp = new Vector();
	temp.add(a);
	temp.add(b);
	temp.add(c);
	temp.add(d);
	tr.t.add(temp);


	temp = new Vector();
	temp.add(a);
	temp.add(b);
	tr.t.add(temp);


	temp = new Vector();
	temp.add(a);
	temp.add(b);
	temp.add(c);
	temp.add(d);
	temp.add(e);
	tr.t.add(temp);

	int tSize = tr.t.size();

	tr.parcel = new Vector(tSize);
	for(int i=0;i<tSize;i++)
		tr.parcel.add(   ((Vector)tr.t.get(i)).get(0) );

	int arr[][] = new int[tSize][2];
	int pr = 1;
	for(int i=(tSize-1);i>=0;i--)
	{
		arr[i][1] = ((Vector)tr.t.get(i)).size();
		arr[i][0] = pr;
		pr *= arr[i][1];
	}

	for(int j=0;j<pr;j++)
	{

		for(int i=0;i<tSize;i++)
		{

		if( (j%arr[i][0]) == 0  ) // remainder of multiple
			{
			  int index = (j/arr[i][0])%arr[i][1]; // remainder of quotient
				//System.out.println("j " + j + " index " + index + " i " + i);  // execute();
			 	tr.parcel.set(i,((Vector)tr.t.get(i)).get(index));

			}

		}

	System.out.println(tr.parcel.toString());  // execute();



	}





}


}