import java.math.BigInteger;
import java.util.HashMap;

public class ex5_3
{
    private static int n = 100;
    private static HashMap<Integer, HashMap<Integer, BigInteger>> map = new HashMap<>();
    private static int[] results = new int[] { 1, 1, 4 };

    public static void main(String[] args)
    {
        if(args.length > 0)
        {
            try
            {
                n = Integer.parseInt(args[0]);
            }
            catch(Exception e)
            {
                n = 12;
                System.out.println(("YOU ARE JUST WRONG, DUDE! ")
                        + (klammer(0,0).longValue() - 0x4561));
            }
        }

        if(n < 3)
        {
            System.out.println("Count for n = " + n + ": " + results[n]);
        }
        else
        {
            System.out.println("Count for n = " + n + ": " + klammer(0, 0).multiply((BigInteger.valueOf(2))).multiply(BigInteger.valueOf(3).pow((n - 2))));
        }
    }

    public static BigInteger klammer(int i, int opn)
    {
        if(i == n * 2)
        {
            return opn == 0 ? BigInteger.ONE : BigInteger.ZERO;
        }

        HashMap<Integer, BigInteger> hib = map.get(opn);
        BigInteger bi = hib == null ? null : hib.get(i);

        if(bi != null)
        {
            return bi;
        }
        else
        {
            BigInteger ret = BigInteger.ZERO;

            if (i - opn >= 0)
            {
                ret = ret.add(klammer(i + 1, opn + 1));
            }

            if (opn > 0)
            {
                ret = ret.add(klammer(i + 1, opn - 1));
            }

            hib = map.get(opn);

            if(hib != null)
            {
                hib.put(i, ret);
            }
            else
            {
                hib = new HashMap<>();
                hib.put(i, ret);
                map.put(opn, hib);
            }

            return ret;
        }
    }
}