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.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;

/**
 * @author Mubtasim Shahriar
 */

public class MaxQuad {

    public static void main(String[] args) {

        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader sc = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
//		int t = sc.nextInt();
        int t = 1;
        while (t-- != 0) {
            solver.solve(sc, out);
        }
        out.close();

    }

    static class Solver {
        public void solve(InputReader sc, PrintWriter out) {
            int n = sc.nextInt();
            Point[] points = new Point[n];
            for (int i = 0; i < n; i++) {
                int x = sc.nextInt();
                int y = sc.nextInt();
                points[i] = new Point(x,y);
            }
            int maxArea = 0;
            for(int i = 0; i < n-1; i++) {
                Point a = points[i];
                for(int j = i + 1; j < n; j++) {
                    Point b = points[j];
                    int left = -1;
                    int right = -1;
                    for(int k = 0; k < n; k++) {
                        if(k==i || k==j) continue;
                        Point c = points[k];
                        long turnright = turnRight(a,b,c);
                        if(turnright<0) right = Math.max(right,getArea(a,b,c));
                        else if(turnright>0) left = Math.max(left,getArea(a,b,c));
                    }
                    if(left!=-1 && right!=-1) maxArea = Math.max(maxArea,left + right);
                }
            }
            out.println((double)maxArea/2);
        }

        private int getArea(Point a, Point b, Point c) {
            return Math.abs(crossProd(minusP(a,c),minusP(b,c)));
        }

        private long turnLeft(Point a, Point b, Point c) {
            Point first = minusP(c,a);
            Point second = minusP(c,b);
            return crossProd(first,second);
        }

        private long turnRight(Point a, Point b, Point c) {
            Point first = minusP(c,a);
            Point second = minusP(c,b);
            return crossProd(first,second);
        }

        private int crossProd(Point first, Point second) {
            return first.x*second.y - second.x*first.y;
        }

        private Point minusP(Point c, Point a) {
            return new Point(c.x-a.x,c.y-a.y);
        }
    }

    static class Point {
        int x, y;

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

    static void sort(int[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
    }

    static void sort(long[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
    }

    static void sortDec(int[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
        int l = 0;
        int r = n - 1;
        while (l < r) {
            arr[l] ^= arr[r];
            arr[r] ^= arr[l];
            arr[l] ^= arr[r];
            l++;
            r--;
        }
    }

    static void sortDec(long[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
        int l = 0;
        int r = n - 1;
        while (l < r) {
            arr[l] ^= arr[r];
            arr[r] ^= arr[l];
            arr[l] ^= arr[r];
            l++;
            r--;
        }
    }

    static class InputReader {
        private boolean finished = false;

        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 peek() {
            if (numChars == -1) {
                return -1;
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    return -1;
                }
                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 - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long 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 String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

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

        private String readLine0() {
            StringBuilder buf = new StringBuilder();
            int c = read();
            while (c != '\n' && c != -1) {
                if (c != '\r') {
                    buf.appendCodePoint(c);
                }
                c = read();
            }
            return buf.toString();
        }

        public String readLine() {
            String s = readLine0();
            while (s.trim().length() == 0) {
                s = readLine0();
            }
            return s;
        }

        public String readLine(boolean ignoreEmptyLines) {
            if (ignoreEmptyLines) {
                return readLine();
            } else {
                return readLine0();
            }
        }

        public BigInteger readBigInteger() {
            try {
                return new BigInteger(nextString());
            } catch (NumberFormatException e) {
                throw new InputMismatchException();
            }
        }

        public char nextCharacter() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            return (char) c;
        }

        public double nextDouble() {
            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, nextInt());
                }
                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, nextInt());
                    }
                    if (c < '0' || c > '9') {
                        throw new InputMismatchException();
                    }
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }

        public boolean isExhausted() {
            int value;
            while (isSpaceChar(value = peek()) && value != -1) {
                read();
            }
            return value == -1;
        }

        public String next() {
            return nextString();
        }

        public SpaceCharFilter getFilter() {
            return filter;
        }

        public void setFilter(SpaceCharFilter filter) {
            this.filter = filter;
        }

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

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

        public int[] nextSortedIntArray(int n) {
            int array[] = nextIntArray(n);
            Arrays.sort(array);
            return array;
        }

        public int[] nextSumIntArray(int n) {
            int[] array = new int[n];
            array[0] = nextInt();
            for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
            return array;
        }

        public long[] nextLongArray(int n) {
            long[] array = new long[n];
            for (int i = 0; i < n; ++i) array[i] = nextLong();
            return array;
        }

        public long[] nextSumLongArray(int n) {
            long[] array = new long[n];
            array[0] = nextInt();
            for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
            return array;
        }

        public long[] nextSortedLongArray(int n) {
            long array[] = nextLongArray(n);
            Arrays.sort(array);
            return array;
        }
    }


}