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


int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<vector<long long>> dp(N + 1, vector<long long>(N + 1, 0LL));
    for (int a = 0; a <= N; ++a) dp[a][0] = 1LL;
    for (int a = 1; a <= N; ++a){
        for (int b = 1; b <= a; ++b){
            dp[a][b] = dp[a - 1][b] + dp[a][b - 1];
        }
    }
    cout << dp[N][N] << endl;
    return 0;
}