#include<stdio.h>
double f(int n)
{
    int i;
    double a=1;
    for(i=1;i<=n;i++)
    a=a*i;
    return a;
}
void main()
{
    int n;
    while(scanf("%d",&n)==1)
    {
       printf("%.lf\n",f(2*n)/(f(n)*f(n)*(n+1)));
    }
}

/**************************************************************
	Problem: 2120
	User: admin
	Language: C
	Result: Accepted
	Time:8 ms
	Memory:1144 kb
****************************************************************/