#include <bits/stdc++.h>
using namespace std;

int main() {
	int n;
	cin >> n;
	vector<vector<long long>> dp(n + 1, vector<long long>(n + 1, 0));

	dp[0][0] = 1;

	for (int i = 0; i < n + 1; ++i) {
		for (int j = 0; j < n + 1; ++j) {
			if (i >= 1 && j >= 1) {
				dp[i][j] += dp[i - 1][j - 1];
			}
			if (i >= 1 && j >= 2) {
				dp[i][j] += dp[i - 1][j - 2];
			}
			if (i >= 2 && j >= 1) {
				dp[i][j] += dp[i - 2][j - 1];
			}
			if (i >= 2 && j >= 2) {
				dp[i][j] += dp[i - 2][j - 2];
			}
		}
	}

	cout << dp[n][n] << endl;
}