Java - If else Statement

import java.io.*;

class ssvif
 {
   public static void main(String arg[]) throws IOException
    {
      System.out.print("Enter your age in completed years: ");

      DataInputStream dr = new DataInputStream(System.in);

      String t;

      t = dr.readLine();

      int age = Integer.parseInt(t);

      if(age >= 18)
         System.out.println("\nyou are eligible to cast your vote");
      else
         System.out.println("\nyou have to wait for " + (18-age) + " years");
   }
 }