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

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Jacob Jiang
 */
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 n = in.nextInt();
        Point[] p = new Point[n];
        for (int i = 0; i < n; i++) {
            p[i] = new Point(in.nextInt(), in.nextInt());
        }
        double answer = 0;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                Point a = p[i], b = p[j];
                Vector ab = Vector.link(a, b);
                double leftMax = Double.NEGATIVE_INFINITY, rightMax = Double.NEGATIVE_INFINITY;
                for (int k = 0; k < n; k++) {
                    if (k != i && k != j) {
                        Point c = p[k];
                        if (ab.cross(Vector.link(a, c)) > 0) {
                            leftMax = Math.max(leftMax, GeometryAlgorithms.triangleArea(a, b, c));
                        } else {
                            rightMax = Math.max(rightMax, GeometryAlgorithms.triangleArea(a, b, c));
                        }
                    }
                }
                answer = Math.max(answer, leftMax + rightMax);
            }
        }
        out.println(answer);
    }
}

class InputReader {

    private InputStream stream;
    private byte[] buf = new byte[1 << 16];
    private int curChar;
    private int numChars;

    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 nextInt() {
        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 & 15;
            c = read();
        } while (!isSpaceChar(c));
        return res * sgn;
    }

    public static boolean isSpaceChar(int c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    }

class OutputWriter {
    private PrintWriter writer;

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

    public OutputWriter(Writer writer) {
        this.writer = new PrintWriter(writer);
    }

    public void println(double x) {
        writer.println(x);
    }

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

    }

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

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

    }

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

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

    public static Vector link(Point from, Point to) {
        return new Vector(to.x - from.x, to.y - from.y);
    }

    public double cross(Vector that) {
        return x * that.y - y * that.x;
    }

    public String toString() {
        return "(" + x + ", " + y + ")";
    }

    }

class GeometryAlgorithms {
    public static double triangleArea(Point a, Point b, Point c) {
        return Math.abs(Vector.link(a, b).cross(Vector.link(a, c))) * .5;
    }
}