using System;

public class Yuki790
{
	public static void Main()
	{
		var n = int.Parse(Console.ReadLine());
		
		var a = 1L;
		for(var i = 0; i < n - 1; ++i) a *= (2 * n - i);
		var b = Factorial(n);

		Console.WriteLine(a / b);
	}
	
	private static long Factorial(int n)
	{
		if(n == 0) return 1L;
		
		return n * Factorial(n - 1);
	}
}