#include <bits/stdc++.h> #define int long long using namespace std; int f[105]; int n; signed main() { cin >> n; f[0] = 1; f[1] = 1; for (int i = 2; i <= n; i++) for (int j = 0; j < i; j++) f[i] += f[j] * f[i - 1 - j]; printf("%lld\n",f[n]); return 0; }