require 'matrix'
ERROR = 1e-5
include Math
class Line
	#ax+by = c   (a > 0 or (a == 0 && b > 0))
	def self.through_two_points(x1, y1, x2, y2)
		a = y1 - y2
		b = x2 - x1
		c = a * x1 + b * y1
		new(a, b, c, x1, y1, x2, y2)
	end

	def cross_point(l)
		m = Matrix[
			[@a, @b],
			[l.a, l.b],
		];
		v = Vector[@c, l.c]
		(m.inv * v).to_a
	end

	private_class_method :new

	def initialize(*args)
		@a, @b, @c, @x1, @y1, @x2, @y2 = args	
	end

	attr_reader :a, :b, :c, :x1, :y1, :x2, :y2
end

n = gets.to_i
points = (1..n).map{ gets.split.map(&:to_i) }
vecs = (points + [points[0]]).each_cons(2).map do |(x1, y1), (x2, y2)|
	Vector[x2 - x1, y2 - y1]
end

R = vecs.map(&:r).inject(:+)

lines = []

get_bisection = -> do
	org = Vector[*points[0]]
	halfs = []
	r = 0
	until r >= R / 2
		halfs << vecs[halfs.size]
		r += halfs[-1].r
	end
	d = halfs[-1].r
	halfs[-1] *= (d - (r - R / 2)) / d
	vecs << vecs.shift
	points << points.shift
	Line.through_two_points(*org.to_a, *halfs.inject(org, &:+))
end

cx, cy = get_bisection[].cross_point(get_bisection[])
ok = (1..n).all? do
	l = get_bisection[]
	hypot(cx - (l.x1 + l.x2) / 2, cy - (l.y1 + l.y2) / 2) < ERROR
end

puts ok ? [cx, cy] * " " : 'NA'