#include <iostream>
#include <vector>
#include <algorithm>

long long dp[28][14][14];

int main() {
    int n;
    std::cin >> n;

    dp[0][0][0] = 1;
    for (int i = 0; i < 2 * n; i++) {
        for (int j = std::min(i, n); j >= 0; j--) {
            for (int k = 0; k <= n; k++) {
                if (j < n) dp[i + 1][j + 1][k + 1] += dp[i][j][k];
                if (k > 0) dp[i + 1][j][k - 1] += dp[i][j][k];
            }
        }
    }

    std::cout << dp[2 * n][n][0] << std::endl;
    return 0;
}