TILING

#include <iostream>

using namespace std;
long long n;

int main()
{
    cin >> n;
    long long *g = new long long[n + 1];
    long long *f = new long long[n + 1];
    g[0] = 0;
    g[1] = 1;
    f[0] = 1;
    f[1] = 1;
    for (long long i = 2; i <= n; ++i)
    {
        g[i] = f[i - 1] + g[i - 1];
        f[i] = f[i - 1] + f[i - 2] + 2 * g[i - 2];
    }
    cout << f[n];
    return 0;
}