#include <bits/stdc++.h> using namespace std; unsigned long long dp[104]; int main(){int n;cin>>n;dp[2] = 1;dp[3] = 1;for(int i = 4;i<=n;i++){for(int j = 2;j<n;j++) dp[i]+=dp[j]*dp[i-j+1];}cout<<dp[n]<<endl;return 0;}