Problem: A convex polygon consisting of N vertices is given. The coordinates of each vertex are represented counterclockwise by (X1, Y1), (X2, Y2), ……, (XN, YN). No matter what straight line passes through the point P, find the coordinates of the point P so that the areas of the two convex polygons obtained after cutting are equal.

Constraints

* All inputs are integers

* 3 ≤ N ≤ 50

* 0 ≤ | Xi |, | Yi | ≤ 1000000

* The input polygon is a simple convex polygon.

* The output must satisfy max (| X-cX |, | Y-cY |) ≤ 0.0001 when the output coordinates are (X, Y) and the exact solution is (cX, cY).

Input

The input is given in the following format.

> N
> X1 Y1
> X2 Y2
> ……
> XN YN
>

Output

If there is a point that satisfies the condition of the problem statement, the coordinates of that point

> X Y
>

Output in the format of. If the point does not exist, output "NA" on one line.

Examples

Input

4
100 100
0 100
0 0
100 0


Output

50.00000 50.00000


Input

3
100 100
0 100
0 0


Output

NA

Solution (in CPP):

Solution:
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
using namespace std;
static const double EPS = 1e-10;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)
#define rev(i,n) for(int i=n-1;i>=0;i--)
#define sz(a) a.size()
#define all(a) a.begin(),a.end()
#define mp(a,b) make_pair(a,b)
#define pb(a) push_back(a)
#define SS stringstream
#define DBG1(a) rep(_X,sz(a)){printf("%d ",a[_X]);}puts("");
#define DBG2(a) rep(_X,sz(a)){rep(_Y,sz(a[_X]))printf("%d ",a[_X][_Y]);puts("");}
#define bitcount(b) __builtin_popcount(b)
#define REP(i, s, e) for ( int i = s; i <= e; i++ )  
 
const double INF = 1e12;
typedef complex<double> P,point;
 
typedef vector<P> G,polygon;
namespace std {bool operator < (const P& a, const P& b) {return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);} }
double cross(const P& a, const P& b) {return imag(conj(a)*b);}
double dot(const P& a, const P& b) {return real(conj(a)*b);}
struct L : public vector<P> {L(const P &a, const P &b) {push_back(a); push_back(b);} };
struct C {P p; double r;C(const P &p, double r) : p(p), r(r) { } C(){} };
int ccw(P a, P b, P c) {
	b -= a; c -= a;
	if (cross(b, c) > 0)   return +1;
	if (cross(b, c) < 0)   return -1;
	if (dot(b, c) < 0) return +2;
	if (norm(b) < norm(c)) return -2;
	return 0;
}
 
// Check Funcs //
bool intersectLL(const L &l, const L &m) {return abs(cross(l[1]-l[0], m[1]-m[0])) > EPS || abs(cross(l[1]-l[0], m[0]-l[0])) < EPS;}
bool intersectLS(const L &l, const L &s) {return cross(l[1]-l[0], s[0]-l[0])*cross(l[1]-l[0], s[1]-l[0]) < EPS;}
bool intersectLP(const L &l, const P &p) {return abs(cross(l[1]-p, l[0]-p)) < EPS;}
bool intersectSS(const L &s, const L &t) {return ccw(s[0],s[1],t[0])*ccw(s[0],s[1],t[1]) <= 0 && ccw(t[0],t[1],s[0])*ccw(t[0],t[1],s[1]) <= 0;}
bool intersectSP(const L &s, const P &p) {return abs(s[0]-p)+abs(s[1]-p)-abs(s[1]-s[0]) < EPS;}
 
// Where is Point in Polygon? //
#define curr(P, i) P[i]
#define next(P, i) P[(i+1)%P.size()]
enum { OUT, ON, IN };
int contains(const polygon& P, const point& p) {
	bool in = false;
	for (int i = 0; i < P.size(); ++i) {
		point a = curr(P,i) - p, b = next(P,i) - p;
		if (imag(a) > imag(b)) swap(a, b);
		if (imag(a) <= 0 && 0 < imag(b))
			if (cross(a, b) < 0) in = !in;
		if (cross(a, b) == 0 && dot(a, b) <= 0) return ON;
	}
	return in ? IN : OUT;
}
// Area of Polygon //
double area2(const polygon& P) {
	double A = 0;
	for (int i = 0; i < P.size(); ++i)A += cross(curr(P, i), next(P, i));
	return A;
}
// Totsuhou! Andrew's Monotone Chain //
 
vector<point> convex_hull(vector<point> ps) {
  int n = ps.size(), k = 0;
  sort(ps.begin(), ps.end());
  vector<point> ch(2*n);
  for (int i = 0; i < n; ch[k++] = ps[i++]) // lower-hull
    while (k >= 2 && ccw(ch[k-2], ch[k-1], ps[i]) <= 0) --k;
  for (int i = n-2, t = k+1; i >= 0; ch[k++] = ps[i--]) // upper-hull
    while (k >= t && ccw(ch[k-2], ch[k-1], ps[i]) <= 0) --k;
  ch.resize(k-1);
  return ch;
}
 
P projection(const L &l, const P &p) {double t = dot(p-l[0], l[0]-l[1]) / norm(l[0]-l[1]);return l[0] + t*(l[0]-l[1]);}
P reflection(const L &l, const P &p) {return p + 2.0 * (projection(l, p) - p);}
 
double distanceLP(const L &l, const P &p) {
	return abs(p - projection(l, p));
}
double distanceLL(const L &l, const L &m) {
	return intersectLL(l, m) ? 0 : distanceLP(l, m[0]);
}
double distanceLS(const L &l, const L &s) {
	if (intersectLS(l, s)) return 0;
	return min(distanceLP(l, s[0]), distanceLP(l, s[1]));
}
double distanceSP(const L &s, const P &p) {
	const P r = projection(s, p);
	if (intersectSP(s, r)) return abs(r - p);
	return min(abs(s[0] - p), abs(s[1] - p));
}
double distanceSS(const L &s, const L &t) {
	if (intersectSS(s, t)) return 0;
	return min(min(distanceSP(s, t[0]), distanceSP(s, t[1])),min(distanceSP(t, s[0]), distanceSP(t, s[1])));
}
 
P crosspoint(const L &l, const L &m) {
	double A = cross(l[1] - l[0], m[1] - m[0]);
	double B = cross(l[1] - l[0], l[1] - m[0]);
	if (abs(A) < EPS && abs(B) < EPS) return m[0];
	return m[0] + B / A * (m[1] - m[0]);
}
 
vector<P> C_cp(C a,C b){
	vector<P> ret;
	double L = abs(a.p-b.p);
 
	/* anma dekitenai */
	if(	L-a.r-b.r > EPS || (abs(a.p-b.p)<EPS && fabs(a.r-b.r)<EPS) || 
		abs(a.p-b.p) < abs(a.r-b.r)
	)return ret;
 
	double theta = atan2(b.p.imag()-a.p.imag(),b.p.real()-a.p.real());
	double c = (L*L+a.r*a.r-b.r*b.r)/(2*L*a.r);
	ret.push_back(
		P(a.p.real()+a.r*cos(theta+acos(c)),
		  a.p.imag()+a.r*sin(theta+acos(c)))
	);
	if(fabs(L-a.r-b.r) > EPS)
		ret.push_back(
			P(a.p.real()+a.r*cos(theta-acos(c)),
			  a.p.imag()+a.r*sin(theta-acos(c)))
		);
	return ret;
}
 
 
P getPedal(L l, P p){
	double A;
	if(abs(l[1].real()-l[0].real()) < EPS){
		return P(l[1].real(),p.imag()); // important
	}else{
		A = (l[1].imag()-l[0].imag())/(l[1].real()-l[0].real());
	}
	double a = -A , b = 1 , c = A*l[0].real() - l[0].imag();
	double t = (a*p.real() + b*p.imag() + c)/(a*a+b*b);
	return p-t * P(a,b);
}
 
vector<P> crosspointCL(const L l, const C c){
	vector<P> ret;
	P p = getPedal(l,c.p);
	if(	abs(p-c.p) > c.r+EPS)return ret;
	P e = P((l[1]-l[0])/abs(l[1]-l[0]));
	double S = sqrt(c.r*c.r-abs(p-c.p)*abs(p-c.p));
	ret.push_back(p+S*e);
	ret.push_back(p-S*e);
	return ret;
}
 
P getCircumcenter(P a,P b,P c){
	double A1 = 2 * ( b.real() - a.real() );
	double B1 = 2 * ( b.imag() - a.imag() );
	double C1 = pow(a.real(),2)-pow(b.real(),2) + pow(a.imag(),2)-pow(b.imag(),2);
	double A2 = 2 * ( c.real() - a.real() );
	double B2 = 2 * ( c.imag() - a.imag() );
	double C2 = pow(a.real(),2)-pow(c.real(),2) + pow(a.imag(),2)-pow(c.imag(),2);
	double X = (B1 * C2 - B2 * C1) / (A1 * B2 - A2 * B1);
	double Y = (C1 * A2 - C2 * A1) / (A1 * B2 - A2 * B1);
	return P(X,Y);
}
 
double AreaOfPolygon(vector<P> p){
	double S = 0 ; 
	p.push_back(p[0]);
	/*???????§???¢?????¢?????¬??? (???????¨????????????´???) */
	for(int i = 0 ; i < p.size()-1 ; i++){
		S += (p[i].real() - p[i+1].real()) * (p[i].imag()+p[i+1].imag());
	}
	S /= 2.0;
	return S;
}

int main(){
	P gr;
	int N;
	cin >> N;
	G g,g2;
	for(int i = 0 ; i < N ; i++){
		int x,y;
		cin >> x >> y;
		g.push_back(P(x,y));
		gr += P(x,y);
	}
	gr /= N;
	for(int i = 0 ; i < N ; i++){
		g[i] -= gr;
	}
	g2 = g;
	for(int i = 0 ; i < N ; i++){
		g2[i] *= exp(P(0,acos(-1)));
		//cout << g2[i] << endl;
	}
	sort(g2.begin(),g2.end());
	sort(g.begin(),g.end());
	for(int i = 0 ; i < N ; i++)
		if( abs(g[i]-g2[i]) > 1e-6 ){
			cout << "NA" << endl;
			return 0;
		}
		
	printf("%.10lf %.10lf\n",gr.real(),gr.imag());
	
	
}