#include <stdio.h>

unsigned long long n, t, t1, t2, t3, i, aux1, aux2;

int main()
{
    freopen("12perm.in","r",stdin);
    freopen("12perm.out","w",stdout);

    scanf("%lld", &n);
    if (n==1) printf("1");
    else if (n==2) printf("2");
    else if (n==3) printf("6");
    else if (n==4) printf("12");
    else
    {
	t1=12;
	t2=6;
	t3=2;
	for (i=5; i<=n; ++i)
	{ 
	    t=t1+t3+2*(i-2);
	    aux1=t1;
	    t1=t;
	    aux2=t2;
	    t2=aux1;
	    t3=aux2;
	}

	printf("%lld", t);
    }

    fclose(stdin);
    fclose(stdout);

    return 0;
}