Neon No In Java - ICSE Examples

A number is said to be neon, if sum of all digits of square of the number is equal to the number.
Input   9, It's square = 81 = 8+1 = 9       ( So 9 is a Neon Number )
Input   25, It's square = 625 = 6+2+5 = 13  ( So 25 is not a Neon Number )

Write a program to find and print neon numbers from different given numbers. this program should terminate / stop it's processing when a negetive number is given as input. Use "for loop" for finding the sum of digits and other process.

import java.util.*;
class neonnumbers
{
    public static void main ()
    {
        Scanner sc = new Scanner (System.in);
        int no;
        for(; ;)
        {
          System.out.println("Enter the number:");
           no=sc.nextInt();
          if(no<0)
          {
              break;
            }
          int s=no*no,sum=0;
          for(;s>0;)
           {
            sum=sum+(s%10);
            s=s/10;
           }
          if(sum==no)
          {
              System.out.println("neon number");
          }
          else
          {
              System.out.println("not a neon number");
          }
        }
    }
}

Output
==========

Enter the number:
23
not a neon number
Enter the number:
34
not a neon number
Enter the number:
9
neon number
Enter the number:
-1