Reading Odd and Even Integers

I can't figure out what to put in here where the ?'s are to get it to read Odd and Even numbers...

import javax.swing.JOptionPane;

public class Even {
public static void main (String args[])
{
String num1;
int n1,odd,even;

num1 = JOptionPane.showInputDialog("Please type in an integer:");

n1 = Integer.parseInt(num1);
odd = ? ;
even = ? ;


if( ? )JOptionPane.showMessageDialog(
null,"The number is "+odd,"Results",JOptionPane.INFORMATION_MESSAGE);
else JOptionPane.showMessageDialog(
null,"The number is "+even,"Results",JOptionPane.INFORMATION_MESSAGE);

System.exit (0);
}
}

Please help!