1 import java.math.BigInteger;
2 import java.util.Scanner;
3
4 public class Main {
5
6 public static void main(String args[]) {
7 Scanner cin = new Scanner(System.in);
8 BigInteger[] c = new BigInteger[101];
9 c[1] = BigInteger.valueOf(1);
10 c[2] = BigInteger.valueOf(2);
11 for (int i = 3; i <= 100; i++) {
12 BigInteger x1 = BigInteger.valueOf(4*i-2);
13 BigInteger x2 = BigInteger.valueOf(i+1);
14 c[i]=c[i-1].multiply(x1).divide(x2);
15 }
16
17 while (cin.hasNext()) {
18 int N = cin.nextInt();
19 if (N==-1)
20 break;
21 else
22 System.out.println(c[N]);
23 }
24 }
25 }
