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

int main()
{
    int N; cin >> N;
    int ans = 0;
    for (int b = 0; b < (1 << (2 * N)); b++) {
        if (__builtin_popcount(b) != N) continue;
        int c = 0;
        for (int i = 0; i < 2*N; i++) {
            if (b & (1 << i)) {
                if (--c < 0) break;
            } else {
                c++;
            }
        }
        if (c == 0) ans++;
    }
    cout << ans << endl;
}