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.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.InputMismatchException;
import java.io.BufferedWriter;
import java.io.PrintWriter;
import java.io.Writer;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.IOException;
/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Alex
 */
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();
	}
	static class TaskB{
		public void solve(int testNumber, InputReader in, OutputWriter out){
			int n = in.ri();
			double res = 0;
			Point[] points = new Point[n];
			for(int i = 0; i < n; i++) points[i] = new Point(in.ri(), in.ri());
			for(int i = 0; i < n; i++) {
				for(int j = i + 1; j < n; j++) {
					double maxabove = 0, maxbelow = 0;
					for(int k = 0; k < n; k++) {
						if(Polygon.over(points[k], points[j], points[i]))
							maxabove = Math.max(maxabove, Polygon.triangleSquare(points[k], points[j], points[i]));
						else maxbelow = Math.max(maxbelow, Polygon.triangleSquare(points[k], points[j], points[i]));
					}
					if(maxabove > 0 && maxbelow > 0) res = Math.max(res, maxabove + maxbelow);
				}
			}
			out.printLine(res);
		}
	}
	static class InputReader{
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;
		private InputReader.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 ri(){
			return readInt();
		}
		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 isWhitespace(c);
		}
		public static boolean isWhitespace(int c){
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
		public interface SpaceCharFilter{
			public boolean isSpaceChar(int ch);
		}
	}
	static class Point{
		public final double x;
		public final double y;
		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;
		}
	}
	static class Polygon{
		public final Point[] vertices;
		public Polygon(Point... vertices){
			this.vertices = vertices.clone();
		}
		public static boolean over(Point a, Point b, Point c){
			return a.x * (b.y - c.y) + b.x * (c.y - a.y) + c.x * (a.y - b.y) < -GeometryUtils.epsilon;
		}
		public static double triangleSquare(Point a, Point b, Point c){
			return Math.abs((a.x - b.x) * (a.y + b.y) + (b.x - c.x) * (b.y + c.y) + (c.x - a.x) * (c.y + a.y)) / 2;
		}
	}
	static class OutputWriter{
		private final PrintWriter writer;
		public OutputWriter(OutputStream outputStream){
			writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
		}
		public OutputWriter(Writer writer){
			this.writer = new PrintWriter(writer);
		}
		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();
		}
	}
	static class GeometryUtils{
		public static double epsilon = 1e-8;
	}
}