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.awt.geom.Line2D;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;

public class P340B {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(in, out);
        out.close();
    }

    static class Task {
        public void solve(InputReader in, PrintWriter out) {
            int n = in.nextInt();
            Point[] l = new Point[n];
            for (int i = 0; i < n; i++) {
                l[i] = new Point(in.nextInt(), in.nextInt());
            }
            double mar = 0;
            for (int i = 0; i < n; i++) {
                for (int j = i + 1; j < n; j++) {
                    double psa = 0, nsa = 0;
                    for (Point p : l) {
                        if (p != l[i] && p != l[j]) {
                            if (Line2D.relativeCCW(p.x, p.y, l[i].x, l[i].y,
                                    l[j].x, l[j].y) > 0) {
                                double pa = area(l[i], l[j], p);
                                if (pa > psa) {
                                    psa = pa;
                                }
                            } else {
                                double na = area(l[i], l[j], p);
                                if (na > nsa) {
                                    nsa = na;
                                }
                            }

                        }
                    }
                    if (psa > 0 && nsa > 0) {
                        double ar = psa + nsa;
                        mar = Math.max(ar, mar);
                    }
                }
            }
            out.println(mar);
        }

        private double area(Point a, Point b, Point c) {
            return Math.abs(0.5 * (a.x * (b.y - c.y) + b.x * (c.y - a.y)
                    + c.x * (a.y - b.y)));
        }

        public class Point {
            double x;
            double y;

            public Point(double d, double e) {
                x = d;
                y = e;
            }

        }
    }

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

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            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 String nextLine() {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }

        public int[] nextIntArray(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++)
                arr[i] = nextInt();
            return arr;
        }

    }
}