#include <bits/stdc++.h>
using namespace std;
const long double EPS = 1e-9;
const long double PI = acos(-1.0);
struct point_i {
  int x, y;
  point_i() {}
  point_i(int _x, int _y) : x(_x), y(_y) {}
  bool operator<(point_i other) const {
    if (x != other.x) return x < other.x;
    return y < other.y;
  }
  bool operator==(point_i other) const {
    return (x == other.x && y == other.y);
  }
};
struct point {
  long double x, y;
  point() {}
  point(long double _x, long double _y) : x(_x), y(_y) {}
  bool operator<(point other) const {
    if (fabs(x - other.x) > EPS) return x < other.x;
    return y < other.y;
  }
  bool operator==(point other) const {
    return (fabs(x - other.x) < EPS && fabs(y - other.y) < EPS);
  }
};
long double dist2(point p1, point p2) {
  return (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
}
long double dist(point p1, point p2) { return sqrt(dist2(p1, p2)); }
int dist2(point_i p1, point_i p2) {
  return (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
}
long double dist(point_i p1, point_i p2) { return sqrt(dist2(p1, p2)); }
point rotate(point p, long double theta) {
  return point(p.x * cos(theta) - p.y * sin(theta),
               p.x * sin(theta) + p.y * cos(theta));
}
struct line {
  long double a, b, c;
};
void pointsToLine(point p1, point p2, line& l) {
  if (fabs(p1.x - p2.x) < EPS) {
    l.a = 1.0, l.b = 0.0, l.c = -p1.x;
  } else {
    l.a = -(long double)(p1.y - p2.y) / (p1.x - p2.x);
    l.b = 1.0;
    l.c = -(long double)(l.a * p1.x) - p1.y;
  }
}
bool areParallel(line l1, line l2) {
  return (fabs(l1.a - l2.a) < EPS && fabs(l1.b - l2.b) < EPS);
}
bool areSame(line l1, line l2) {
  return (areParallel(l1, l2) && fabs(l1.c - l2.c) < EPS);
}
bool areIntersect(line l1, line l2, point& p) {
  if (areParallel(l1, l2)) return false;
  p.x = (l1.c * l2.b - l2.c * l1.b) / (l2.a * l1.b - l1.a * l2.b);
  if (fabs(l1.b) > EPS)
    p.y = -(l1.a * p.x + l1.c);
  else
    p.y = -(l2.a * p.x + l2.c);
  return true;
}
struct vec {
  long double x, y;
  vec(long double _x, long double _y) : x(_x), y(_y) {}
};
vec toVec(point p1, point p2) { return vec(p2.x - p1.x, p2.y - p1.y); }
vec scale(vec v, long double s) { return vec(s * v.x, s * v.y); }
point translate(point p, vec v) { return point(p.x + v.x, p.y + v.y); }
long double dot(vec v1, vec v2) { return (v1.x * v2.x + v1.y * v2.y); }
long double norm2(vec v) { return dot(v, v); }
long double distToLine(point p, point a, point b, point& c) {
  vec ap = toVec(a, p);
  vec ab = toVec(a, b);
  long double u = dot(ap, ab) / norm2(ab);
  c = translate(a, scale(ab, u));
  return dist(p, c);
}
long double distToSegment(point p, point a, point b, point& c) {
  vec ap = toVec(a, p);
  vec ab = toVec(a, b);
  long double u = dot(ap, ab) / norm2(ab);
  if (u < 0.0) {
    c = point(a.x, a.y);
    return dist(p, a);
  } else if (u > 1.0) {
    c = point(b.x, b.y);
    return dist(p, b);
  }
  return distToLine(p, a, b, c);
}
const int MAX = 100009;
const long double oo = 1e12;
int n;
point arr[MAX];
point P;
int main() {
  ios::sync_with_stdio(false);
  int a, b;
  cin >> n >> a >> b;
  P = point(a, b);
  for (int i = 0; i < n; i++) cin >> arr[i].x >> arr[i].y;
  long double Min = oo, Max = 0.0;
  for (int i = 0; i < n; i++) Max = max(Max, dist(P, arr[i]));
  for (int i = 0; i < n; i++) {
    int j = (i + 1) % n;
    point r;
    Min = min(Min, distToSegment(P, arr[i], arr[j], r));
  }
  cout << fixed << setprecision(15) << (Max * Max - Min * Min) * PI << endl;
  return 0;
}
