#include <bits/stdc++.h>
using namespace std;
const double INF = 1e18;
const double pi = acos(-1.0);
struct Point {
  double x, y;
  Point() {}
  Point(double x, double y) {
    this->x = x;
    this->y = y;
  }
  void read() { scanf("%lf%lf", &x, &y); }
};
Point operator+(Point A, Point B) { return Point(A.x + B.x, A.y + B.y); }
Point operator-(Point A, Point B) { return Point(A.x - B.x, A.y - B.y); }
Point operator*(Point A, double p) { return Point(A.x * p, A.y * p); }
Point operator/(Point A, double p) { return Point(A.x / p, A.y / p); }
bool operator<(const Point& a, const Point& b) {
  return a.x < b.x || (a.x == b.x && a.y < b.y);
}
const double eps = 1e-8;
int dcmp(double x) {
  if (fabs(x) < eps)
    return 0;
  else
    return x < 0 ? -1 : 1;
}
bool operator==(const Point& a, const Point& b) {
  return dcmp(a.x - b.x) == 0 && dcmp(a.y - b.y) == 0;
}
double Dot(Point A, Point B) { return A.x * B.x + A.y * B.y; }
double Length(Point A) { return sqrt(Dot(A, A)); }
double Angle(Point A, Point B) {
  return acos(Dot(A, B) / Length(A) / Length(B));
}
double Cross(Point A, Point B) { return A.x * B.y - A.y * B.x; }
double Area2(Point A, Point B, Point C) { return Cross(B - A, C - A); }
struct Line {
  Point v, p;
  Line() {}
  Line(Point v, Point p) {
    this->v = v;
    this->p = p;
  }
  Point point(double t) { return v + p * t; }
};
Point Rotate(Point A, double rad) {
  return Point(A.x * cos(rad) - A.y * sin(rad),
               A.x * sin(rad) + A.y * cos(rad));
}
Point AngleBisector(Point p, Point v1, Point v2) {
  double rad = Angle(v1, v2);
  return Rotate(v1, dcmp(Cross(v1, v2)) * 0.5 * rad);
}
bool LineCoincide(Point p1, Point p2, Point p3) {
  return dcmp(Cross(p2 - p1, p3 - p1)) == 0;
}
bool LineParallel(Point v, Point w) { return Cross(v, w) == 0; }
bool LineVertical(Point v, Point w) { return Dot(v, w) == 0; }
Point GetLineIntersection(Point P, Point v, Point Q, Point w) {
  Point u = P - Q;
  double t = Cross(w, u) / Cross(v, w);
  return P + v * t;
}
double DistanceToLine(Point P, Point A, Point B) {
  Point v1 = B - A, v2 = P - A;
  return fabs(Cross(v1, v2)) / Length(v1);
}
double DistanceToSegment(Point P, Point A, Point B) {
  if (A == B) return Length(P - A);
  Point v1 = B - A, v2 = P - A, v3 = P - B;
  if (dcmp(Dot(v1, v2)) < 0)
    return Length(v2);
  else if (dcmp(Dot(v1, v3)) > 0)
    return Length(v3);
  else
    return fabs(Cross(v1, v2)) / Length(v1);
}
Point GetLineProjection(Point P, Point A, Point B) {
  Point v = B - A;
  return A + v * (Dot(v, P - A) / Dot(v, v));
}
bool SegmentProperIntersection(Point a1, Point a2, Point b1, Point b2) {
  double c1 = Cross(a2 - a1, b1 - a1), c2 = Cross(a2 - a1, b2 - a1),
         c3 = Cross(b2 - b1, a1 - b1), c4 = Cross(b2 - b1, a2 - b1);
  return dcmp(c1) * dcmp(c2) < 0 && dcmp(c3) * dcmp(c4) < 0;
}
bool SegmentProperIntersection2(Point a1, Point a2, Point b1, Point b2) {
  double c1 = Cross(a2 - a1, b1 - a1), c2 = Cross(a2 - a1, b2 - a1),
         c3 = Cross(b2 - b1, a1 - b1), c4 = Cross(b2 - b1, a2 - b1);
  return max(a1.x, a2.x) >= min(b1.x, b2.x) &&
         max(b1.x, b2.x) >= min(a1.x, a2.x) &&
         max(a1.y, a2.y) >= min(b1.y, b2.y) &&
         max(b1.y, b2.y) >= min(a1.y, a2.y) && dcmp(c1) * dcmp(c2) <= 0 &&
         dcmp(c3) * dcmp(c4) <= 0;
}
bool OnSegment(Point p, Point a1, Point a2) {
  return dcmp(Cross(a1 - p, a2 - p)) == 0 && dcmp(Dot(a1 - p, a2 - p)) < 0;
}
double PolygonArea(Point* p, int n) {
  double area = 0;
  for (int i = 1; i < n - 1; i++) area += Cross(p[i] - p[0], p[i + 1] - p[0]);
  return area / 2;
}
int isPointInPolygon(Point o, Point* p, int n) {
  int wn = 0;
  for (int i = 0; i < n; i++) {
    if (OnSegment(o, p[i], p[(i + 1) % n])) return -1;
    int k = dcmp(Cross(p[(i + 1) % n] - p[i], o - p[i]));
    int d1 = dcmp(p[i].y - o.y);
    int d2 = dcmp(p[(i + 1) % n].y - o.y);
    if (k > 0 && d1 <= 0 && d2 > 0) wn++;
    if (k < 0 && d2 <= 0 && d1 > 0) wn--;
  }
  if (wn != 0) return 1;
  return 0;
}
int ConvexHull(Point* p, int n, Point* ch) {
  sort(p, p + n);
  int m = 0;
  for (int i = 0; i < n; i++) {
    while (m > 1 && Cross(ch[m - 1] - ch[m - 2], p[i] - ch[m - 2]) <= 0) m--;
    ch[m++] = p[i];
  }
  int k = m;
  for (int i = n - 2; i >= 0; i--) {
    while (m > k && Cross(ch[m - 1] - ch[m - 2], p[i] - ch[m - 2]) <= 0) m--;
    ch[m++] = p[i];
  }
  if (n > 1) m--;
  return m;
}
const int N = 100005;
int n;
Point p, a[N];
int main() {
  scanf("%d", &n);
  p.read();
  double Max = -INF, Min = INF;
  for (int i = 0; i < n; i++) {
    a[i].read();
    Max = max(Length(a[i] - p), Max);
  }
  for (int i = 1; i <= n; i++) {
    double tmp = DistanceToSegment(p, a[i - 1], a[i % n]);
    Min = min(tmp, Min);
  }
  printf("%.12f\n", (Max * Max - Min * Min) * pi);
  return 0;
}
