#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;

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

    ll ans = 0;

    for(int bit = 0; bit < (1<<(2*n)); bit++){
        int cnt = 0;
        bool ok = true;
        for(int i=0; i<2*n; i++){
            if(bit & (1<<i)) cnt++;
            else cnt--;
            if(cnt < 0){
                ok = false;
                break;
            }
        }
        if(cnt != 0) ok = false;
        ans += ok;
    }

    cout << ans << endl;

    return 0;
}