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

int dfs(int n, int current, int val) {
    if(2*n == current) {
        if(val == 0) return 1;
        else return 0;
    }
    int ret = 0;
    ret += dfs(n, current+1, val+1);
    if(val > 0) ret += dfs(n, current+1, val-1);
    return ret;
}

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

    int result = dfs(n, 0, 0);

    cout << result << endl;
}