#include <iostream>
using namespace std;

int main() {
    int n; cin >> n;
    long long C[30][30] = {};
    for (int i = 0; i <= 2*n; i++) {
        C[i][0] = C[i][i] = 1;
        for (int j = 1; j < i; j++) C[i][j] = C[i-1][j-1] + C[i-1][j];
    }
    cout << C[2*n][n] / (n+1) << endl;
}