#include <stdio.h>

FILE *f,*s;

int n,a,b,c,d;

int main()
{
	f=fopen("12perm.in","r");
	s=fopen("12perm.out","w");
	
	fscanf(f,"%d",&n);
	
	a=1;
	b=2;
	c=6;
	
	for(int i=4;i<=n;i++)
	{
		d=c+a+2*(i-2);
		
		a=b;
		b=c;
		c=d;
	}	
	
	if(n==1)
		fprintf(s,"1");
	
	if(n==2)
		fprintf(s,"2");
	
	if(n==3)
		fprintf(s,"6");
	
	if(n>3)
		fprintf(s,"%d",d);
	
	fclose(s);
	
	return 0;
}