//======================================
// Problem: 10007 - Count the Trees
// Author: Hsing-Yen Ann
// Date: 2006/03/03
//======================================

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
  // Read until (n<=0)
  while (true) {
    int n;
    cin >> n;
    if (n <= 0) {
      break;
    }

    vector<int> result;
    result.push_back(1);
    
    // 計算 
    for (int i = n+2; i <= 2*n; i++) {
      for (int j = 0; j < result.size(); j++) {
        result[j] *= i;
      }
      // 處理 overflow 
      for (int j = 0; j < result.size() - 1; j++) {
        result[j+1] += (result[j] / 10000);
        result[j] %= 10000;
      }
      int k = result.size()-1;
      if (result[k] >= 10000) {
         result.push_back(result[k] / 10000);
         result[k] %= 10000;
      }
    }

    // 印出結果 
    cout << result[result.size() - 1];
    for (int i = result.size() - 2; i >= 0; i--) {
      cout << (result[i] / 1000) % 10;
      cout << (result[i] / 100) % 10;
      cout << (result[i] / 10) % 10;
      cout << (result[i] / 1) % 10;
    }
    cout << endl;
  }

  return 0;
}