#include <iostream>
#include <algorithm>
#include <vector>
#include <utility>
#include <queue>
#include <math.h>
#include <stdio.h>
#define eps 1e-9

using namespace std;

int n;
double x[55], y[55];
double distPP(double x, double y, double x2, double y2)
{
	return sqrt((x-x2)*(x-x2) + (y-y2)*(y-y2));
}

int main(void)
{
	cin >> n;
	for(int i = 0; i < n; i++) cin >> x[i] >> y[i];
	
	if(n % 2){
		cout << "NA" << endl;
		return 0;
	}
	
	double mx = (x[0]+x[n/2])/2, my = (y[0]+y[n/2])/2;
	for(int i = 0; i < n; i++){
		if(distPP(mx, my, (x[i]+x[(n/2+i)%n])/2, (y[i]+y[(n/2+i)%n])/2) > eps){
			cout << "NA" << endl;
			return 0;
		}
	}
	printf("%.11f %.11f\n", mx, my);
	
	return 0;
}
