#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
const int maxn=20;
int n,ans=0,d[maxn];
bool test(int row,int col)
{
	for(int i=1;i<row;i++)
	{
		if(d[i]==col||d[i]-(row-i)==col||d[i]+(row-i)==col)
		  return false;
	}
	return true;
}
void dfs(int dep)
{
	if(dep>=n+1)
	{
		ans++;
		return;
	}
	for(int i=1;i<=n;i++)
	{
		if(test(dep,i))
		{
			d[dep]=i;
			dfs(dep+1);
		}
	}
}
int main()
{
	freopen("queen.in","r",stdin);
	freopen("queen.out","w",stdout);
	scanf("%d",&n);
	memset(d,0,sizeof(d));
	dfs(1);
	printf("%d\n",ans);
	return 0;
}