Peter got a new snow blower as a New Year present. Of course, Peter decided to try it immediately. After reading the instructions he realized that it does not work like regular snow blowing machines. In order to make it work, you need to tie it to some point that it does not cover, and then switch it on. As a result it will go along a circle around this point and will remove all the snow from its path.

Formally, we assume that Peter's machine is a polygon on a plane. Then, after the machine is switched on, it will make a circle around the point to which Peter tied it (this point lies strictly outside the polygon). That is, each of the points lying within or on the border of the polygon will move along the circular trajectory, with the center of the circle at the point to which Peter tied his machine.

Peter decided to tie his car to point P and now he is wondering what is the area of ​​the region that will be cleared from snow. Help him.


-----Input-----

The first line of the input contains three integers — the number of vertices of the polygon n ($3 \leq n \leq 100000$), and coordinates of point P.

Each of the next n lines contains two integers — coordinates of the vertices of the polygon in the clockwise or counterclockwise order. It is guaranteed that no three consecutive vertices lie on a common straight line.

All the numbers in the input are integers that do not exceed 1 000 000 in their absolute value.


-----Output-----

Print a single real value number — the area of the region that will be cleared. Your answer will be considered correct if its absolute or relative error does not exceed 10^{ - 6}. 

Namely: let's assume that your answer is a, and the answer of the jury is b. The checker program will consider your answer correct, if $\frac{|a - b|}{\operatorname{max}(1, b)} \leq 10^{-6}$.


-----Examples-----
Input
3 0 0
0 1
-1 2
1 2

Output
12.566370614359172464

Input
4 1 -1
0 0
1 2
2 0
1 1

Output
21.991148575128551812



-----Note-----

In the first sample snow will be removed from that area:

 $0$

Difficulty: competition

Starter code:

Solutions:
import math
def dist(x, y, x1, y1, x2, y2):
    a = x-x1
    b = y-y1
    c = x2-x1
    d = y2-y1
    dot = a*c+b*d
    lensq = c*c+d*d
    param=-1
    if lensq != 0:
        param = dot / lensq
    if param < 0:
        xx = x1
        yy = y1
    elif param > 1:
        xx = x2
        yy = y2
    else:
        xx = x1 + param * c
        yy = y1 + param * d

    dx = x - xx
    dy = y - yy
    return (dx*dx+dy*dy)**0.5
def dist2(x, y):
    return ((x[0]-y[0])**2+(x[1]-y[1])**2)**0.5
import math
maxx = -1
minn = 100000000000000000
pts = []
a, b, c = list(map(int, input().split(' ')))
for i in range(a):
    x, y = list(map(int, input().split(' ')))
    pts.append([x, y])

k = []
for i in pts:
    k.append(dist2(i, [b, c]))
pts.append(pts[0])
for i in range(a):
    k.append(dist(b, c, pts[i][0], pts[i][1], pts[i+1][0], pts[i+1][1]))

print((max(k)**2-min(k)**2)*math.pi)


from math import hypot, pi, copysign


def main():
    n, a, b = list(map(int, input().split()))
    l, res = [], []
    for _ in range(n):
        x0, y0 = list(map(int, input().split()))
        l.append((x0 - a, y0 - b))
    x0, y0 = l[-1]
    for x1, y1 in l:
        res.append(hypot(x1, y1))
        dx, dy = x1 - x0, y1 - y0
        if copysign(1., x0 * dx + y0 * dy) != copysign(1., x1 * dx + y1 * dy):
            res.append(abs(x0 * y1 - x1 * y0) / hypot(dx, dy))
        x0, y0 = x1, y1
    print((max(res) ** 2 - min(res) ** 2) * pi)


def __starting_point():
    main()

__starting_point()

def main():
    n, a, b = list(map(int, input().split()))
    l, res = [], []
    for _ in range(n):
        u, v = input().split()
        l.append((int(u) - a, int(v) - b))
    x0, y0 = l[-1]
    for x1, y1 in l:
        res.append(x1 * x1 + y1 * y1)
        dx, dy = x1 - x0, y1 - y0
        if (x0 * dx + y0 * dy) * (x1 * dx + y1 * dy) < 0:
            x0 = x0 * y1 - x1 * y0
            res.append(x0 * x0 / (dx * dx + dy * dy))
        x0, y0 = x1, y1
    print((max(res) - min(res)) * 3.141592653589793)


def __starting_point():
    main()

__starting_point()

s = input().split()
n = int(s[0])

px = int(s[1])
py = int(s[2])


y = []
x = []

for i in range(n):
   s=input().split()
   x.append(int(s[0]) - px)
   y.append(int(s[1]) - py)
   #print(x[i],y[i])

l = []
x0, y0 = x[-1], y[-1]

for i in range(n):
   l.append(x[i]*x[i] + y[i]*y[i])
   dx, dy = x[i] - x0, y[i] - y0
   if (x0*dx+y0*dy)*(x[i]*dx + y[i]*dy) < 0:
      x0 = x0*y[i]-x[i]*y0
      l.append(x0*x0/(dx*dx+dy*dy))
   x0,y0 = x[i],y[i]

a =  3.141592653589793 * (max(l) -min(l))
#print (px,py)
#print (x[imax],y[imax])
#print (x[imin],y[imin])
#print (((px - x[imax])*(px - x[imax]) + (py - y[imax])*(py - y[imax]))) 
#print (((px - x[imin])*(px - x[imin]) + (py - y[imin])*(py - y[imin])))

print (a)



# -*- coding: utf-8 -*-

import sys
import math

def dist2(x1, y1, x2, y2):
    return (x1 - x2) ** 2 + (y1 - y2) ** 2

def find_dist(x1, y1, x2, y2, X, Y):
    if x2 == x1:
        if min(y1, y2) <= Y <= max(y1, y2):
            return (x1 - X) ** 2
        else:
            return min(dist2(x1, y1, X, Y), dist2(x2, y2, X, Y))
    a = (y2 - y1) / (x2 - x1)
    b = y1 - a * x1
    x = (X + a * (Y - b)) / (1 + a * a)
    if min(x1, x2) <= x <= max(x1, x2):
        return dist2(x, a * x + b, X, Y)
    else:
        return min(dist2(x1, y1, X, Y), dist2(x2, y2, X, Y))

def main():
    N, X, Y = list(map(int, sys.stdin.readline().split()))
    maxr = 0
    minr = 10**15
    pts = [tuple(map(int, sys.stdin.readline().split())) for _ in range(N)]
    pts.append(pts[0])
    for i in range(0, len(pts)-1):
        x, y = pts[i]
        r = dist2(x, y, X, Y)
        if r > maxr:
            maxr = r
        r = find_dist(x, y, pts[i+1][0], pts[i+1][1], X, Y)
        if r < minr:
            minr = r

    print("%.10f" % (math.pi * (maxr - minr)))

def __starting_point():
    main()

__starting_point()

import math

def main():
	(n, xp, yp) = (int(x) for x in input().split())
	polygon = [None] * n
	for i in range(n):
		(xi, yi) = (int(x) for x in input().split())
		polygon[i] = (xi, yi)
	print(solver((xp, yp), polygon))

def solver(P, polygon):
	n = len(polygon)
	(xp, yp) = P
	distances = [distance(xp, yp, x, y) for (x, y) in polygon]
	maxDist = max(distances)
	minDist = min(distances)
	for i in range(n):
		p = perpenPoint(polygon[i%n], polygon[(i+1)%n], P)
		if p != None:
			dist = distance(xp, yp, p[0], p[1])
			if dist < minDist:
				minDist = dist
	area = math.pi * (maxDist**2 - minDist**2)
	return area



# ax + by = c
def toLine(point1, point2):
	(x1, y1) = point1
	(x2, y2) = point2
	if x1 == x2:
		if y1 == y2:
			assert(False)
		else:
			return (1, 0, x1)
	else:
		a = (y2 - y1) / (x1 - x2)
		c = a * x1 + y1
		return (a, 1, c)

# perpendicular point from point to the line segment: point1 to point3
def perpenPoint(point1, point2, point):
	line = toLine(point1, point2)
	(a, b, c) = line
	# perpendicular line
	if a == 0:
		(ap, bp) = (b, a)
	else:
		(ap, bp) = (-b / a, 1)
	(x, y) = point
	cp = ap * x + bp * y
	(xi, yi) = intersection(line, (ap, bp, cp))
	(x1, y1) = point1
	(x2, y2) = point2
	if min(x1, x2) <= xi and xi <= max(x1, x2) and \
	min(y1, y2) <= yi and yi <= max(y1, y2):
		return (xi, yi)
	else:
		return None

def intersection(line1, line2):
	(a1, b1, c1) = line1
	(a2, b2, c2) = line2
	if b1 == 0 and a2 == 0:
		return (c1, c2)
	elif a1 == 0 and b2 == 0:
		return (c2, c1)
	else:
		x = (b2 * c1 - b1 * c2) / (a1 * b2 - a2 * b1)
		y = (c1 - a1 * x) / b1
		return (x, y)

def almostEqual(x, y):
	return abs(x - y) < 10**-16

def distance(x1, y1, x2, y2):
	leg1 = abs(x1 - x2)
	leg2 = abs(y1 - y2)
	return (leg1**2 + leg2**2)**0.5

main()
#print(perpenPoint((-1, 0), (0, 1), (1.1, 0)))
#print(perpenPoint((-2, 0), (-2, 1), (0, 0)))
#print(perpenPoint((-1, 1), (2, 1), (0, 0)))
#print(perpenPoint((-1, 0), (1, 1), (0, 0)))
#print(12.56637061435 / math.pi)
#print(solver((0, 0), [(0, 1), (-1, 2), (1, 2)]))
#print(solver((1, -1), [(0, 0), (1, 2), (2, 0), (1, 1)]))


__author__ = 'vboldovs'

#A613

import math

GLOBAL_INNER_PRODUCT_LIMIT  = math.pow(10,-3)

class point:
    def __init__(self,x,y):
        self.x = x
        self.y = y
class line:
    def __init__(self,start_point, end_point):
        self.x = end_point.x - start_point.x
        self.y = end_point.y - start_point.y

def distance(p1,p2):
    return math.sqrt(math.pow(p1.x-p2.x,2)+math.pow(p1.y-p2.y,2))

def product(line1,line2):
    return line1.x*line2.x+line1.y*line2.y

m = input().split()
n = int(m[0])
center = point(int(m[1]), int(m[2]))

points = []

for _i in range(n):
    temp = input().split()
    points.append(point(int(temp[0]),int(temp[1])))

max_r = distance(center,points[0])
min_r = max_r

for p in points:
    d = distance(p,center)
    max_r = max(max_r,d)
    min_r = min(min_r,d)

for i in range(n):
    s_point = points[i]
    try:
        e_point = points[i+1]
    except IndexError:
        e_point = points[0]
    curr_line = line(s_point,e_point)

    prod_s = product(curr_line,line(s_point,center))
    prod_e = product(curr_line,line(e_point,center))

    if prod_s*prod_e>0:
        continue

    alpha = prod_s/abs(prod_e-prod_s)
    p_point = point((1-alpha)*s_point.x+alpha*e_point.x,(1-alpha)*s_point.y+alpha*e_point.y)

    min_r = min(min_r, distance(p_point,center))

    #alpha = 0.5
    #while True:
    #    test_point = point((1-alpha)*s_point.x+alpha*e_point.x,(1-alpha)*s_point.y+alpha*e_point.y)
    #    prod = product(line(test_point,center),curr_line)
    #
    #    if abs(prod) <= GLOBAL_INNER_PRODUCT_LIMIT:
    #        min_r = min(min_r,distance(test_point,center))
    #        break

    #    if prod > GLOBAL_INNER_PRODUCT_LIMIT:
    #        alpha+=alpha/2
    #    else:
    #        alpha-=alpha/2

print(math.pi*math.pow(max_r,2)-math.pi*math.pow(min_r,2))








from math import *

def dist(a,b,p):
	xu = b[0]-a[0]
	yu = b[1]-a[1]
	xv = p[0]-a[0]
	yv = p[1]-a[1]
	c1 = xu*xv + yu*yv
	c2 = xu*xu + yu*yu
	x,y = 0,0
	if c1<=0:
		x = a[0]-p[0]
		y = a[1]-p[1]
	elif c2<=c1:
		x = b[0]-p[0]
		y = b[1]-p[1]
	else:
		x = a[0] + xu*(c1/c2)-p[0]
		y = a[1] + yu*(c1/c2)-p[1]
	return x*x + y*y


n,cx,cy = map(int,input().split())
pts =  [ list(map(int,input().split())) for _ in range(n) ]
mini,maxi = float('inf'),0
for i in range(n):
	px,py = pts[i]
	maxi = max((px-cx)**2+(py-cy)**2,maxi)
	mini = min(dist(pts[i-1],pts[i],[cx,cy]),mini)
print((maxi-mini)*pi)

def dot_product(v1, v2):
    return v1.x * v2.x + v1.y * v2.y


class vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def length(self):
        return (self.x ** 2 + self.y ** 2) ** 0.5

    def cross_product(self, v):
        return self.x * v.y - self.y * v.x

class line:
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def distance(self, p):
        return abs(vector(p.x - self.a.x, p.y - self.a.y).cross_product(vector(p.x - self.b.x, p.y - self.b.y)) / vector(self.a.x - self.b.x, self.a.y - self.b.y).length())

class ray:
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def distance(self, p):
        if dot_product(vector(self.b.x - self.a.x, self.b.y - self.a.y), vector(p.x - self.a.x, p.y - self.a.y)) >= 0:
            return line(self.a, self.b).distance(p)
        return vector(self.a.x - p.x, self.a.y - p.y).length()

class segment:
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def min_distance(self, p):
        if dot_product(vector(self.b.x - self.a.x, self.b.y - self.a.y), vector(p.x - self.a.x, p.y - self.a.y)) >= 0:
            return ray(self.b, self.a).distance(p)
        return vector(self.a.x - p.x, self.a.y - p.y).length()

    def max_distance(self, p):
        return max(vector(self.a.x - p.x, self.a.y - p.y).length(), vector(self.b.x - p.x, self.b.y - p.y).length())


n, x, y = map(int, input().split())
p = vector(x, y)

min_r = 2000000
max_r = 0

a = [[] for i in range(n + 1)]

for i in range(n):
    a[i] = list(map(int, input().split()))
    a[i] = vector(a[i][0], a[i][1])

a[n] = a[0]

for i in range(n):
    s = segment(a[i], a[i + 1])
    min_r = min(min_r, s.min_distance(p))
    max_r = max(max_r, s.max_distance(p))

pi = 3.141592653589
print(pi * max_r ** 2 - pi * min_r ** 2)

import math
n, px, py = map(int, input().split())
xs, ys, l = list(), list(), list()
for _ in range(n):
	x, y = map(int, input().split())
	xs.append(x - px)
	ys.append(y - py)
x0, y0 = xs[-1], ys[-1]
for x, y in zip(xs, ys):
	l.append(x * x + y * y)
	dx, dy = x - x0, y - y0
	if (x0 * dx + y0 * dy) * (x * dx + y * dy) < 0:
		x0 = x0 * y - x * y0
		l.append(x0 * x0 / (dx * dx + dy * dy))
	x0, y0 = x, y
print(math.pi * (max(l) - min(l)))

def main():
    n, a, b = list(map(int, input().split()))
    l, res = [], []
    for _ in range(n):
        u, v = input().split()
        l.append((int(u) - a, int(v) - b))
    x0, y0 = l[-1]
    for x1, y1 in l:
        res.append(x1 * x1 + y1 * y1)
        dx, dy = x1 - x0, y1 - y0
        if (x0 * dx + y0 * dy) * (x1 * dx + y1 * dy) < 0:
            x0 = x0 * y1 - x1 * y0
            res.append(x0 * x0 / (dx * dx + dy * dy))
        x0, y0 = x1, y1
    print((max(res) - min(res)) * 3.141592653589793)


def __starting_point():
    main()




# Made By Mostafa_Khaled

__starting_point()

import math


def Len (w):
    return w[0] * w[0] + w[1] * w[1]

n, x, y = input().split(' ')
n = int(n)
x = int(x)
y = int(y)

arr = []

for i in range(0, n):
    a, b = input().split(' ')
    a = int(a)
    b = int(b)
    arr.append([a, b])

r1 = 5000000000000
r2 = -500000000000

for i in range(0, n):
    st = [arr[(i + 1) % n][0] - arr[i][0], arr[(i + 1) % n][1] - arr[i][1]]
    r = [arr[i][0] - x, arr[i][1] - y]
    q = [arr[(i + 1) % n][0] - x, arr[(i + 1) % n][1] - y]
    d = q[0] * r[1] - q[1] * r[0]
    d *= d
    s = d/Len(st)
    if Len (q) - s < Len (st) and Len(r) - s < Len(st):
        r1 = min(r1, s)
        r2 = max(r2, s)

for i in arr:
    s = (x - i[0]) * (x - i[0]) + (y - i[1]) * (y - i[1])
    r1 = min(r1, s)
    r2 = max(r2, s)

print ((r2 - r1) * math.pi)

import functools
 
class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y
 
    def squared_distance(self, another_point):
        return (self.x - another_point.x) ** 2 + (self.y - another_point.y) ** 2

def point_segment_distance(p, a, b):
    ap = (p.x - a.x, p.y - a.y)
    ab = (b.x - a.x, b.y - a.y)
    bp = (p.x - b.x, p.y - b.y)

    indicator = (ap[0] * ab[0] + ap[1] * ab[1]) / (ab[0] ** 2 + ab[1] ** 2)
    if 0 < indicator < 1:
        return (ap[0] ** 2 + ap[1] ** 2) - indicator ** 2 * (ab[0] ** 2 + ab[1] ** 2)
    if indicator <= 0:
        return ap[0] ** 2 + ap[1] ** 2
    if indicator >= 1:
        return bp[0] ** 2 + bp[1] ** 2
 
class SnowBlower:       
    def solution(self):
        first_line = input()
        first_line = first_line.split(" ")
        num_vertices = int(first_line[0])
        origin = Point(int(first_line[1]), int(first_line[2]))
 
        vertices = []
        for _ in range(num_vertices):
            point = input()
            point = point.split(" ")
            vertices.append(Point(int(point[0]), int(point[1])))
 
        max_distance = float("-inf")
        min_distance = float("inf")
        for vertex in vertices:
            squared_distance = origin.squared_distance(vertex)
            max_distance = squared_distance if squared_distance > max_distance else max_distance
 
 
        for i in range(num_vertices):
            distance = point_segment_distance(origin, vertices[i], vertices[i - 1])
            min_distance = distance if distance < min_distance else min_distance
 
 
        pi = 3.14159265358
        
        print(pi * (max_distance - min_distance))
 
 
def __starting_point():
    snow_blower = SnowBlower()
    snow_blower.solution()
__starting_point()

import math

def dot(v1, v2):
    return v1[0]*v2[0] + v1[1]*v2[1]

def cross(v1, v2):
    return v1[0]*v2[1] - v1[1]*v2[0]

def mag(x,y):
    return math.sqrt(x**2 + y**2)

def main():
    PI = 3.141592653589793
    mags = []
    
    n, x0, y0 = map(int, input().split())

    x, y = x0, y0
    for i in range(n):
        x_, y_ = map(int, input().split())
        x_, y_ = x_ - x0, y_ - y0
        if i == 0:
            x1, y1 = x_ , y_
            x, y = x_, y_

        mags.append(mag(x_,y_))    

        if dot([x,y],[x-x_, y-y_])*dot([x_,y_],[x_-x,y_-y]) > 0:
            mags.append(abs(cross([x,y],[x_-x,y_-y])) / mag(x-x_,y-y_))
    
        x, y = x_, y_

    if dot([x,y],[x-x1,y-y1])*dot([x1,y1],[x1-x,y1-y]) > 0:
        mags.append(abs(cross([x,y],[x1-x,y1-y])) / mag(x-x1,y-y1))

    print((max(mags)**2 - min(mags)**2) * PI)

def __starting_point():
    main()
__starting_point()

import math

def dotproduct(point1, point2):
    x1, y1 = point1
    x2, y2 = point2
    product = (x1 * x2) + (y1 * y2)
    return product

def crossproduct(point1, point2):
    x1, y1 = point1
    x2, y2 = point2
    product = (x1 * y2) - (y1 * x2)
    return product

def magnitude(x, y):
    mag = math.sqrt(x**2 + y**2)
    return mag

def main():
    magnitudes = []

    n, x0, y0 = list(map(int, input().split()))

    x = x0
    y = y0
    for i in range(n):
        x2, y2 = list(map(int, input().split()))
        x2 = x2 - x0
        y2 = y2 - y0

        if (i == 0):
            x1 = x2
            y1 = y2
            x = x2
            y = y2

        magnitudes.append(magnitude(x2, y2))

        dot1 = dotproduct([x,y],[x - x2, y - y2])
        dot2 = dotproduct([x2, y2], [x2 - x, y2 - y])

        if ((dot1 * dot2) > 0):
            total = abs(crossproduct([x, y], [x2 - x, y2 - y]) / magnitude(x - x2, y - y2))
            magnitudes.append(total)

        x = x2
        y = y2

    dot3 = dotproduct([x, y], [x - x1, y - y1])
    dot4 = dotproduct([x1, y1], [x1 - x, y1 - y])

    if ((dot3 * dot4) > 0):
        total1 = abs(crossproduct([x, y], [x1 - x, y1 - y]) / magnitude(x - x1, y - y1))
        magnitudes.append(total1)

    print((max(magnitudes)**2 - min(magnitudes)**2) * 3.141592653589793)

def __starting_point():
    main()


__starting_point()

""" Peter and Snow Blower """
import math


def cross(vecA, vecB):
    return abs(vecA[0] * vecB[1] - vecA[1] * vecB[0])


def l2_norm(pointA, pointB):
    return (pointA[0] - pointB[0]) ** 2 + (pointA[1] - pointB[1]) ** 2


def height5(P, A, B):
    a = l2_norm(A, P)
    b = l2_norm(B, P)
    base = l2_norm(A, B)

    # If obtuse triangles
    if a >= base + b or b >= base + a:
        return min(a, b)

    else:
        # If acute triangles
        vecA = (A[0] - P[0], A[1] - P[1])
        vecB = (B[0] - P[0], B[1] - P[1])
        area = cross(vecA, vecB)
        h = area * area / base
        return h


def CF613A():
    # Read number of points, center and the points
    N, cx, cy = list(map(int, input().split()))
    points = [tuple(map(int, input().split())) for _ in range(N)]

    # N, cx, cy = 3, 0, 0  # 12.56
    # points = [(0, 1), (-1, 2), (1, 2)]
    #
    # N, cx, cy = 4, 1, -1  # 21.99
    # points = [(0, 0), (1, 2), (2, 0), (1, 1)]
    #
    # N, cx, cy = 3, 0, 0  # 25.13
    # points = [(-1, 1), (0, 3), (1, 1)]
    #
    # N, cx, cy = 3, -4, 2  # 405.26
    # points = [(-3, 2), (5, -5), (5, 3)]

    # Compute the max distance
    center = (cx, cy)
    distances = [l2_norm(center, point) for point in points]
    max_radius = max(distances)

    # Compute the min distance
    min_radius = float('inf')
    for i in range(N):
        height = height5(center, points[i], points[(i + 1) % N])
        min_radius = min(min_radius, height)

    area = math.pi * (max_radius - min_radius)
    return area


def __starting_point():
    res = CF613A()
    print(res)

__starting_point()

""" Peter and Snow Blower """
import math


def cross(vecA, vecB):
    return abs(vecA[0] * vecB[1] - vecA[1] * vecB[0])


def l2_norm(pointA, pointB):
    return (pointA[0] - pointB[0]) ** 2 + (pointA[1] - pointB[1]) ** 2


def height5(P, A, B):
    a = l2_norm(A, P)
    b = l2_norm(B, P)
    base = l2_norm(A, B)

    # If obtuse triangles
    if a >= base + b or b >= base + a:
        return min(a, b)

    else:
        # If acute triangles
        vecA = (A[0] - P[0], A[1] - P[1])
        vecB = (B[0] - P[0], B[1] - P[1])
        area = cross(vecA, vecB)
        h = area * area / base
        return h


def CF613A():
    # Read number of points, center and the points
    N, cx, cy = list(map(int, input().split()))
    points = [tuple(map(int, input().split())) for _ in range(N)]

    # Compute the max distance
    center = (cx, cy)
    distances = [l2_norm(center, point) for point in points]
    max_radius = max(distances)

    # Compute the min distance
    min_radius = float('inf')
    for i in range(N):
        height = height5(center, points[i], points[(i + 1) % N])
        min_radius = min(min_radius, height)

    area = math.pi * (max_radius - min_radius)
    return area


def __starting_point():
    res = CF613A()
    print(res)

__starting_point()

import math

def dis(a0, b0, x, y):
    return ((a0-x) ** 2 + (b0-y) ** 2) ** 0.5
    
# distance from point to segment
def minDistance(A, B, E) :  
   
    AB = [B[0] - A[0], B[1] - A[1]]  
    BE = [E[0] - B[0], E[1] - B[1]]
    AE = [E[0] - A[0], E[1] - A[1]]
  
    AB_BE = AB[0] * BE[0] + AB[1] * BE[1];  
    AB_AE = AB[0] * AE[0] + AB[1] * AE[1];  
  
    reqAns = 0;  
  
    # Case 1  
    if AB_BE > 0: 
        # Finding the magnitude  
        y = E[1] - B[1] 
        x = E[0] - B[0]  
        return (x * x + y * y) ** 0.5 
  
    # Case 2  
    elif (AB_AE < 0) : 
        y = E[1] - A[1] 
        x = E[0] - A[0]  
        return (x * x + y * y) ** 0.5
  
    # Case 3  
    else: 
        # Finding the perpendicular distance  
        x1, y1, x2, y2 = AB[0], AB[1], AE[0], AE[1]  
        mod    = (x1 * x1 + y1 * y1) ** 0.5
        
        return abs(x1 * y2 - y1 * x2) / mod
    
n, x0, y0 = map(int, input().split())
P    = [list(map(int, input().split())) for _ in range(n)]

max_ = 0
min_ = float("inf")

for i in range(n):
    p    = P[i]
    
    min_ = min(min_, minDistance(P[i], P[(i+1)%n], [x0, y0]))
    max_ = max(max_, dis(x0, y0, p[0], p[1]))
    
print(math.pi * (max_ * max_ - min_ * min_))