UVa 10198 - Counting

// UVa 10198 - Counting

import java.math.*;
import java.util.*;

public class Main {

	public static void main(String[] args) {
		
		BigInteger[] T = new BigInteger[1001];
		T[0] = new BigInteger("1");
		T[1] = new BigInteger("2");
		T[2] = new BigInteger("5");
		for (int i=3; i<=1000; i++){
			T[i] = new BigInteger("0");
			T[i] = T[i].add(T[i-1]).add(T[i-1]).add(T[i-2]).add(T[i-3]);
		}

		Scanner scanner = new Scanner(System.in);	
		
		while (scanner.hasNextInt()){
			int n = scanner.nextInt();
			System.out.printf("%s\n",T[n].toString());
		}
			
	}
}