public class NQueen1
{
	static int n;
	static int[] x;
	static long sum;
	
	public static long nQueen(int nn)
	{
		n=nn;
		sum=0;
		x=new int[n+1];
		for(int i=0;i<=n;i++) x[i]=0;
		backtrack(1);
		return sum;
	}
	private static boolean place(int k)
	{
		for(int j=1;j<k;j++)
		if((Math.abs(k-j)==Math.abs(x[j]-x[k]))||(x[j]==x[k]))return false;
		return true;
	}
	private static void backtrack(int t)
	{
		if(t>n) sum++;
		else
		   for(int i=1;i<=n;i++)
		     x[t]=i;
//System.out.println(x[t]);	
		     if(place(t))
		      backtrack(t+1);
		     
	}
	public static void main(String args[])
	{
	 
	 System.out.println(nQueen(4));	   
	}
}