#include <bits/stdc++.h>

#define REP(i, n) for (int i = 0; i < n; i++)
#define llINF ((long long)1e18)
#define INF ((int)1e9);
#define ALL(obj) obj.begin(), obj.end()

using namespace std;

int N;

long long rec(int right, int left) {
    if (right < left) return 0;
    if (right > N || left > N) return 0;
    if (right == N && left == N) return 1;
    long long res = rec(right + 1, left) + rec(right, left + 1);
    return res;
}

int main() {
    cin >> N;
    cout << rec(0, 0) << endl;
}