Problem: Iahub has drawn a set of n points in the cartesian plane which he calls "special points". A quadrilateral is a simple polygon without self-intersections with four sides (also called edges) and four vertices (also called corners). Please note that a quadrilateral doesn't have to be convex. A special quadrilateral is one which has all four vertices in the set of special points. Given the set of special points, please calculate the maximal area of a special quadrilateral. 

Input

The first line contains integer n (4 ≤ n ≤ 300). Each of the next n lines contains two integers: xi, yi ( - 1000 ≤ xi, yi ≤ 1000) — the cartesian coordinates of ith special point. It is guaranteed that no three points are on the same line. It is guaranteed that no two points coincide. 

Output

Output a single real number — the maximal area of a special quadrilateral. The answer will be considered correct if its absolute or relative error does't exceed 10 - 9.

Examples

Input

5
0 0
0 4
4 0
4 4
2 3


Output

16.000000

Note

In the test example we can choose first 4 points to be the vertices of the quadrilateral. They form a square by side 4, so the area is 4·4 = 16.

Solution (in JAVA):

Solution:
/**
 * @author cplayer on 2018/6/23.
 * @version 1.0
 */

import java.util.*;
import java.util.stream.IntStream;
import java.io.*;
import java.lang.*;
import java.math.BigInteger;

public class Main {

    public static void main(String[] args) {
        try {
            InputReader in;
            PrintWriter out;
            boolean useOutput = false;
            if (System.getProperty("ONLINE_JUDGE") == null) useOutput = true;
            if (useOutput) {
                FileInputStream fin = new FileInputStream(new File("src/data.in"));
                in = new InputReader(fin);
                FileOutputStream fout = new FileOutputStream(new File("src/data.out"));
                out = new PrintWriter(fout);
            } else {
                InputStream inputStream = System.in;
                in = new InputReader(inputStream);
                OutputStream outputStream = System.out;
                out = new PrintWriter(outputStream);
            }
            Solver solver = new Solver(in, out);
            solver.solve();
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    static class Solver {

        private InputReader cin;
        private PrintWriter cout;

        Solver (InputReader cin, PrintWriter cout) {
            this.cin = cin; this.cout = cout;
        }

        private double getCross (double x1, double y1, double x2, double y2) {
            return x1 * y2 - y1 * x2;
        }

        public void solve () {
            try {
                int n = cin.nextInt();
                double co[][] = new double[n][2];
                for (int i = 0; i < n; ++i) {
                    co[i][0] = cin.nextDouble(); co[i][1] = cin.nextDouble();
                }
                double ret = 0;
                for (int i = 0; i < n; ++i) {
                    for (int j = 0; j < n; ++j) {
                        if (j == i) continue;
                        double x = co[i][0] - co[j][0];
                        double y = co[i][1] - co[j][1];
                        double resPos = 0, resNeg = 0;
                        for (int k = 0; k < n; ++k) {
                            if (k == j || k == i) continue;
                            double x1 = co[i][0] - co[k][0];
                            double y1 = co[i][1] - co[k][1];
                            double tmp = getCross(x, y, x1, y1) * 0.5;
                            if (tmp > 0) {
                                resPos = Math.max(resPos, tmp);
                            } else if (tmp < 0) {
                                resNeg = Math.max(resNeg, -1.0 * tmp);
                            }
                        }
                        if (resPos > 0 && resNeg > 0) ret = Math.max(ret, resPos + resNeg);
                    }
                }
                cout.println(ret);
            } catch (RuntimeException e) {
                e.printStackTrace();
                return;
            } catch (Exception e) {
                e.printStackTrace();
                return;
            }

        }
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 1000000);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

    }

}