#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
int ans;
vector<int> a;
int n;
bool c[100];
void DFS(int x)
{
	c[x]=1;
    a.push_back(x);
	if(x==n)
	{
		ans++;
		a.pop_back();
		c[x]=0;
		return;
	}
	for(int i=x;i<=n;i++)
		DFS(i);	
	a.pop_back();
	c[x]=0;
	return;
}
int main()
{
	
	cin>>n;
	DFS(1);
	cout<<ans;
	return 0;
}