#include <bits/stdc++.h>
using namespace std;
template <class T>
T Bitcnt(T a) {
  int sum = 0;
  while (a) {
    if (a & 1) sum++;
    a /= 2;
  }
  return sum;
}
template <class T>
T Max3(T a, T b, T c) {
  return max(a, max(b, c));
}
template <class T>
T Lcm(T a, T b) {
  T tmp = __gcd(a, b);
  return (a / tmp) * b;
}
template <class T>
T Pow(T a, T b) {
  T ans = 1;
  T base = a;
  while (b) {
    if (b & 1) ans = (ans * base);
    base = (base * base);
    b /= 2;
  }
  return ans;
}
long long Bigmod(long long a, long long b) {
  long long res = 1;
  long long pw = a % 1000000007LL;
  while (b > 0) {
    if (b & 1) res = (res * pw) % 1000000007LL;
    pw = (pw * pw) % 1000000007LL;
    b /= 2;
  }
  return res;
}
int a_x[] = {1, -1, 0, 0};
int a_y[] = {0, 0, 1, -1};
long long X, Y;
void extend_euclid(long long a, long long b) {
  if (b == 0) {
    X = a;
    Y = 0;
    return;
  }
  extend_euclid(b, a % b);
  long long x, y;
  x = Y;
  y = X - (a / b) * Y;
  X = x;
  Y = y;
}
long long inverse_modulo(long long a, long long b) {
  extend_euclid(a, b);
  return (X + 1000000007LL) % 1000000007LL;
}
double dist(double x1, double y1, pair<double, double> tmp) {
  double t = 1LL * (x1 - tmp.first) * (x1 - tmp.first) +
             1LL * (y1 - tmp.second) * (y1 - tmp.second);
  return (t);
}
int n;
pair<int, int> inp[200005];
double dist1(int indx1, int indx2, int x, int y) {
  double lx, ly, rx, ry, ltx, lty, rtx, rty;
  lx = inp[indx1].first;
  ly = inp[indx1].second;
  rx = inp[indx2].first;
  ry = inp[indx2].second;
  int tot = 100;
  double ans = (long long)1e18;
  while (tot--) {
    ltx = (lx * 2 + rx) / 3.0;
    lty = (ly * 2 + ry) / 3.0;
    rtx = (lx + rx * 2) / 3.0;
    rty = (ly + ry * 2) / 3.0;
    if (dist(ltx, lty, make_pair(x, y)) - dist(rtx, rty, make_pair(x, y)) <
        1e-13) {
      rx = rtx;
      ry = rty;
      ans = min(ans, dist(ltx, lty, make_pair(x * 1.0, y * 1.0)));
    } else {
      lx = ltx;
      ly = lty;
      ans = min(ans, dist(rtx, rty, make_pair(x * 1.0, y * 1.0)));
    }
  }
  return ans;
}
double dist2(int indx1, int indx2, int x, int y) {
  double lx, ly, rx, ry, ltx, lty, rtx, rty;
  lx = inp[indx1].first;
  ly = inp[indx1].second;
  rx = inp[indx2].first;
  ry = inp[indx2].second;
  int tot = 100;
  double ans = 0.0;
  while (tot--) {
    ltx = (lx * 2 + rx) / 3.0;
    lty = (ly * 2 + ry) / 3.0;
    rtx = (lx + rx * 2) / 3.0;
    rty = (ly + ry * 2) / 3.0;
    if (dist(ltx, lty, make_pair(x, y)) - dist(rtx, rty, make_pair(x, y)) >
        1e-13) {
      rx = rtx;
      ry = rty;
      ans = max(ans, dist(ltx, lty, make_pair(x * 1.0, y * 1.0)));
    } else {
      lx = ltx;
      ly = lty;
      ans = max(ans, dist(rtx, rty, make_pair(x * 1.0, y * 1.0)));
    }
  }
  return ans;
}
int main() {
  int n;
  scanf("%d", &n);
  double mx = 0.0;
  double mn = (long long)1e18;
  int x, y;
  scanf("%d %d", &x, &y);
  for (int i = 0; i <= n - 1; i++) {
    int a, b;
    scanf("%d %d", &a, &b);
    inp[i] = make_pair(a, b);
  }
  for (int i = 0; i <= n - 1; i++) {
    int f = i;
    int s = (i + 1) % n;
    double res = dist1(f, s, x, y);
    mn = min(res, mn);
    res = dist2(f, s, x, y);
    mx = max(res, mx);
  }
  double ans;
  ans = acos(-1.0) * (mx - mn);
  printf("%.12lf\n", ans);
  return 0;
}
