#include <iostream>
using namespace std;

int main()
{
	int n;
	cout << "\n n = ?";
	cin >> n;

	int j[n + 1];
	j[0] = 0;
	j[1] = 1;

	if (n >= 2)
	{
		for (int i = 2; i <= n; i++)
		{
			j[i] = j[i - 1] + 2 * j[i - 2];
		}
	}

	cout << " => J(" << n << ") = " << j[n] << endl << endl;

	system("pause");
}