import java.util.*;
import java.math.*;

public class Main{
    public static void main(String[] args){
    Scanner in = new Scanner(System.in);
    while(in.hasNextInt()){
        int n = in.nextInt();
        int i = n;
        int j = n*2;
        BigInteger up = BigInteger.valueOf(i);
        BigInteger down = BigInteger.valueOf(j);
        BigInteger a = BigInteger.valueOf(0);
        for(int k = i, l = 1;l<i;k--,l++)
            up = up.multiply(BigInteger.valueOf(k - 1));
        for(int k = j, l = 1;l<i;k--,l++)
            down = down.multiply(BigInteger.valueOf(k - 1));
            a = down.divide(up).divide(BigInteger.valueOf(n+1));
        System.out.println(a);
    }
}
}
/**************************************************************
	Problem: 2120
	User: admin
	Language: Java
	Result: Accepted
	Time:804 ms
	Memory:40116 kb
****************************************************************/