#include <bits/stdc++.h>

using namespace std;
int n;
int res;
stack<char> stk;
bool check(string t) {
    stack<char>().swap(stk);
    for (int i = t.size() - 1; i >= 0; i--) {
        if (!stk.empty() && stk.top() == '}' && t[i] == '{')
            stk.pop();
        else
            stk.push(t[i]);
    }
    return stk.size() == 0;
}
void dfs(int u, string t) {
    if (u == 2 * n + 1) {
        if (check(t)) res++;
        return;
    }

    dfs(u + 1, t + "{");
    dfs(u + 1, t + "}");
}
int main() {
    cin >> n;
    dfs(1, "");
    cout << res << endl;
    return 0;
}