import java.applet.Applet;
import java.awt.event.*;
import java.awt.*;



public class aa extends Applet implements  ActionListener ,Runnable{
 Label prompt;
 TextField tf;
 Button btn;
 int limnum;
 Thread thread1;




public void init()
{prompt =new Label("請輸入上限：");
tf=new TextField(10);
btn=new Button("開始");
add(prompt);
add(tf);
add(btn);
btn.addActionListener(this);
}

public void actionPerformed(ActionEvent e)
{
  if(e.getSource()==btn) 
    limnum=Integer.parseInt(tf.getText());
   repaint();
}
public void start()
{thread1=new Thread(this,"Thread");
thread1.start();}

public int zhishu(int number){
for (int i=2;i<number;i++)
  if(number%i==0)  return 0;
  return 1;
}

public void run(){}
public void paint(Graphics g){
for(int i=1;i<=limnum;i++)
{if(zhishu(i)==1) g.setColor(Color.green);
else g.setColor(Color.red);
g.drawString(" /n  ",0,0);
g.drawString(""+i,10+i%4*120,20+i/4*15);
}}

}