#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; }