import java.util.*;
import java.util.zip.*;
import java.util.List;
import java.util.regex.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.concurrent.locks.*;
import java.util.function.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.table.*;
import java.io.*;
import java.net.*;
import java.lang.reflect.*;
import java.lang.ref.*;
import java.lang.management.*;
import java.security.*;
import java.security.spec.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.awt.geom.*;
import javax.imageio.*;
import java.math.*;
import java.time.Duration;
import java.lang.invoke.VarHandle;
import java.lang.invoke.MethodHandles;
import java.awt.geom.*;

class main {



static float drawArrowHead_length = 2f;

static void drawArrowHead(Graphics2D g, double x1, double y1, double x2, double y2, double size) {
  if (y2 == y1 && x2 == x1) return;
  
  Path2D.Double arrowHead = new Path2D.Double();
  arrowHead.moveTo(0, 0);
  double l = drawArrowHead_length*size;
  arrowHead.lineTo(-size, -l);
  arrowHead.lineTo(size, -l);
  arrowHead.closePath();

  AffineTransform tx = new AffineTransform();
  double angle = Math.atan2(y2-y1, x2-x1);
  tx.translate(x2, y2);
  tx.rotate(angle-Math.PI/2);

  AffineTransform old = g.getTransform();
  g.transform(tx);
  g.fill(arrowHead);
  g.setTransform(old);
}}