#define Y scanf("%lf%lf",x+p, y+p)
#define Z(k) (k[0]+k[1])/2
int main()
{
	double x[3], y[3];
	int n, p; while (scanf("%d", &n) > 0)
	{ 
		printf("%d ", n); 
		p = 0; 
		Y; 
		x[2] = x[0]; y[2] = y[0]; p = 1; 
		while (--n)
		{ 
			Y;
			printf("%lf %lf ", Z(x), Z(y)); p ^= 1; 
		}
		x[p] = x[2]; y[p] = y[2]; 
		printf("%lf %lf ", Z(x), Z(y)); 
		putchar(10); 
	}
}