#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-10;
const int inf = 0x3f3f3f3f;
const double pi = acos(-1);
const int mod = 100000000;
double max(double a, double b) { return a > b ? a : b; };
double min(double a, double b) { return a < b ? a : b; };
const int max_ = 100000;
struct Point {
  double x, y;
  Point(double xx, double yy) : x(xx), y(yy) {}
  Point(){};
} p[max_ + 5];
Point o;
Point operator-(Point a, Point c) { return Point(a.x - c.x, a.y - c.y); }
int n;
double Dot(Point a, Point b) { return a.x * b.x + a.y * b.y; }
double dist(Point a, Point b) { return sqrt(Dot(a - b, a - b)); }
double Cross(Point a, Point b) { return fabs(a.x * b.y - b.x * a.y); }
double Pointtoline(Point o, Point a, Point b) {
  return Cross(o - a, b - a) / dist(a, b);
}
double Pointtosegment(Point o, Point a, Point b) {
  if (Dot(o - a, b - a) < 0)
    return dist(o, a);
  else if (Dot(o - b, a - b) < 0)
    return dist(o, b);
  else
    return Pointtoline(o, a, b);
}
int main() {
  while (~scanf("%d %lf %lf", &n, &o.x, &o.y)) {
    double minn = inf, maxn = 0;
    for (int i = 0; i < n; i++) scanf("%lf %lf", &p[i].x, &p[i].y);
    p[n] = p[0];
    for (int i = 0; i < n; i++) {
      double temp = Pointtosegment(o, p[i], p[i + 1]);
      minn = min(minn, temp);
      maxn = max(maxn, dist(p[i], o));
    }
    printf("%.18f\n", pi * (maxn * maxn - minn * minn));
  }
  return 0;
}
