#include<bits/stdc++.h> #define int long long using namespace std; int a[30] = {0,1,2,5,14,42,132,429,1430,4862,16796,58786,208012,742900,2674440,9694845,35357670,129644790,477638700,1767263190,6564120420,24466267020,91482563640,343059613650,1289904147324,4861946401452}; signed main(){ long long t; while (cin>>t && t != 0){ cout<<a[t]<<'\n'; } return 0; }