I

#include <bits/stdc++.h>

using namespace std;

#define fixed(n) fixed << setprecision(n)
#define ceil(n, m) (((n) + (m) - 1) / (m))
#define add_mod(a, b, m) (((a % m) + (b % m)) % m)
#define sub_mod(a, b, m) (((a % m) - (b % m) + m) % m)
#define mul_mod(a, b, m) (((a % m) * (b % m)) % m)
#define all(vec) vec.begin(), vec.end()
#define rall(vec) vec.rbegin(), vec.rend()
#define sz(x) int(x.size())
#define debug(x) cout << #x << ": " << (x) << "\n";
#define fi first
#define se second
#define ll long long
#define ull unsigned long long
#define EPS 1e-9
constexpr int INF = 1 << 30, Mod = 1e9 + 7;
constexpr ll LINF = 1LL << 62;
#define PI acos(-1)
template < typename T = int > using Pair = pair < T, T >;
vector < string > RET = {"NO", "YES"};

template < typename T = int > istream& operator >> (istream &in, vector < T > &v) {
    for (auto &x : v) in >> x;
    return in;
}

template < typename T = int > ostream& operator << (ostream &out, const vector < T > &v) {
    for (const T &x : v) out << x << ' ';
    return out;
}

typedef complex < double > point;
#define X real()
#define Y imag()
#define angle(a)                (atan2((a).imag(), (a).real()))
#define vec(a, b)                ((b)-(a))
#define same(p1, p2)             (dp(vec(p1, p2), vec(p1,p2)) < EPS)
#define dp(a, b)                 ( (conj(a) * (b)).real() ) // a * b cos(T), if zero -> prep
#define cp(a, b)                 ( (conj(a) * (b)).imag() ) // a * b sin(T), if zero -> parllel
#define length(a)               (hypot((a).imag(), (a).real()))
#define normalize(a)            (a) / length(a)
#define polar(r, ang)            ((r) * exp(point(0, ang)))
#define rotateO(p, ang)          ((p) * exp(point(0, ang)))
#define rotateA(p, ang, about)  (rotateO(vec(about, p), ang) + about)
int dcmp(double a, double b) { return fabs(a - b) <= EPS ? 0 : a < b ? -1 : 1; }

istream& operator >> (istream &in, point& p) {
    double x, y;
    in >> x >> y;
    p = point(x, y);
    return in;
}

ostream& operator << (ostream &out, const point& p) {
    out << p.X << ' ' << p.Y;
    return out;
}

double dist(point& a, point& b) {
    return hypot(a.X - b.X, a.Y - b.Y);
}

double TriangleArea(point& a, point& b, point& c) {
    return fabs(cp(b - a, c - a)) / 2.0;
}

void Solve(){
    int n;
    cin >> n;
    point S;
    cin >> S;
    deque < point > P(n);
    for(auto& p : P)
        cin >> p;
    sort(all(P), [&](point& a, point& b) {
        return dist(S, a) < dist(S, b);
    });
    double MaxArea = 0;
    vector < int > next(n, -1), nextnext(n, -1);
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            if(i == j) continue;
            double distA = dist(P[i], P[j]);
            if(next[i] == -1)
                next[i] = j;
            else if(distA < dist(P[i], P[next[i]]))
                nextnext[i] = next[i], next[i] = j;
            else if(nextnext[i] == -1 || distA < dist(P[i], P[nextnext[i]]))
                nextnext[i] = j;
        }
    }
    vector < bool > is_removed(n, false);
    for(int i = 0; i < n; i++){
        is_removed[i] = true;
        double MinArea = 1e18;
        for(int j = 0; j < n; j++){
            if(i == j) continue;
            if(!is_removed[next[j]])
                MinArea = min(MinArea, TriangleArea(S, P[j], P[next[j]]));
            else
                MinArea = min(MinArea, TriangleArea(S, P[j], P[nextnext[j]]));
        }
        MaxArea = max(MaxArea, MinArea);
        is_removed[i] = false;
    }
    cout << fixed(10) << MaxArea << '\n';
}

int main(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    int test_cases = 1;
    // cin >> test_cases;
    for(int tc = 1; tc <= test_cases; tc++){
        // cout << "Case #" << tc << ": ";
        Solve();
    }
    return 0;
}