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:
import java.io.BufferedWriter;
import java.util.InputMismatchException;
import java.io.InputStream;
import java.util.NoSuchElementException;
import java.io.OutputStreamWriter;
import java.math.BigInteger;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.io.IOException;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Nguyen Trung Hieu - vuondenthanhcong11@gmail.com
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        OutputWriter out = new OutputWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
}

class TaskB {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
        int count = in.readInt();
        Point[] points = new Point[count];
        for (int i = 0; i < count; i++) {
            points[i] = Point.readPoint(in);
        }

        double answer = 0.0;

        for (int i = 0; i < count; i++) {
            for (int j = i + 1; j < count; j++) {
                double maxVal1 = 0.0;
                double maxVal2 = 0.0;

                for (int k = 0; k < count; k++) {
                    if (Point.isClockWiseOrColinear(points[j], points[k], points[i]))
                        maxVal1 = Math.max(maxVal1, GeometryUtils.calculateArea(new Point[]{points[i], points[j], points[k]}));
                    else
                        maxVal2 = Math.max(maxVal2, GeometryUtils.calculateArea(new Point[]{points[i], points[j], points[k]}));
                }

                if (maxVal1 > 0.0 && maxVal2 > 0.0)
                    answer = Math.max(answer, maxVal1 + maxVal2);
            }
        }

        out.printLine(answer);
    }
}

class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private SpaceCharFilter filter;

    public InputReader(InputStream stream) {
        this.stream = stream;
    }

    public int read() {
        if (numChars == -1)
            throw new InputMismatchException();
        if (curChar >= numChars) {
            curChar = 0;
            try {
                numChars = stream.read(buf);
            } catch (IOException e) {
                throw new InputMismatchException();
            }
            if (numChars <= 0)
                return -1;
        }
        return buf[curChar++];
    }

    public int readInt() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        int res = 0;
        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return res * sgn;
    }

    public boolean isSpaceChar(int c) {
        if (filter != null)
            return filter.isSpaceChar(c);
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
        public boolean isSpaceChar(int ch);
    }

    public double readDouble() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        double res = 0;
        while (!isSpaceChar(c) && c != '.') {
            if (c == 'e' || c == 'E')
                return res * Math.pow(10, readInt());
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        }
        if (c == '.') {
            c = read();
            double m = 1;
            while (!isSpaceChar(c)) {
                if (c == 'e' || c == 'E')
                    return res * Math.pow(10, readInt());
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                m /= 10;
                res += (c - '0') * m;
                c = read();
            }
        }
        return res * sgn;
    }

}

class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
        writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public void print(Object...objects) {
        for (int i = 0; i < objects.length; i++) {
            if (i != 0)
                writer.print(' ');
            writer.print(objects[i]);
        }
    }

    public void printLine(Object...objects) {
        print(objects);
        writer.println();
    }

    public void close() {
        writer.close();
    }

}

class Point {
    public final double x;
    public final double y;

    //update 24/8/2013
    public String toString() {
        return "(" + x + ", " + y + ")";
    }

    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }

    public boolean equals(Object o) {
        if (this == o)
            return true;
        if (o == null || getClass() != o.getClass())
            return false;

        Point point = (Point) o;

        return Math.abs(x - point.x) <= GeometryUtils.epsilon && Math.abs(y - point.y) <= GeometryUtils.epsilon;
    }

    public int hashCode() {
        int result;
        long temp;
        temp = x != +0.0d ? Double.doubleToLongBits(x) : 0L;
        result = (int) (temp ^ (temp >>> 32));
        temp = y != +0.0d ? Double.doubleToLongBits(y) : 0L;
        result = 31 * result + (int) (temp ^ (temp >>> 32));
        return result;
    }

    public static Point readPoint(InputReader in) {
        double x = in.readDouble();
        double y = in.readDouble();
        return new Point(x, y);
    }

    public static boolean isClockWiseOrColinear(Point A, Point B, Point C) {
        double x0 = A.x - C.x;
        double y0 = A.y - C.y;
        double x1 = B.x - C.x;
        double y1 = B.y - C.y;
        double s = (x0 * y1) - (x1 * y0);
        return s <= GeometryUtils.epsilon;
    }
}

class GeometryUtils {
    public static double epsilon = 1e-8;

    public static double calculateArea(Point[] points) {
        double answer = 0.0;
        int count = points.length;
        if (count <= 2)
            return 0.0;
        for (int i = 1; i < count; i++)
            answer += points[i - 1].x * points[i].y - points[i - 1].y * points[i].x;
        answer += points[count - 1].x * points[0].y - points[count - 1].y * points[0].x;
        answer /= 2.0;
        return Math.abs(answer);
    }
}