// UUID: 38abd05e-d744-461c-b32d-e8512b20c87b
#include <bits/stdc++.h>
#include <vector>
using namespace std;

int main() {
	int n; cin >> n;
	vector<pair<int,int>> dp(n + 1);
	dp[1].first = 2;
	dp[1].second = 2;
	dp[0].second = 1;
	for (int i = 2;i <= n;i++) {
		dp[i].first = 2 * dp[i - 2].second + dp[i - 1].first + 2 * dp[i - 1].second;
		dp[i].second = /*1x1 block*/(dp[i].first - dp[i - 1].second/2) + dp[i - 1].second + dp[i - 1].first;
	}
	cout << dp[n].second;
}