Secure the given valid id's by making 1st 9 digit as *(star)

valid id is identified by following condition.
1) Even places of a number sum is greater than the odd places sum.
2)It's consists of 13 digit
i/p:
 1234567890123
o/p:
*********0123 
 
import java.util.*;
public class NewClass12 {
       void print(String k)
       {
           System.out.println(k);
       }
      String secure(String s)
      {
         char c[]=s.toCharArray();
         int odd=0,even=0;
         for(int i=0;i<c.length;i++)
         {
             if(i%2==0)
             {
                 even+=(c[i]-'0');
             }else
             {
                 odd+=(c[i]-'0');
             }
         }
         if(even>odd)
         {
             for(int i=0;i<9;i++)
                 c[i]='*';
         }
         return String.valueOf(c);
      }
      public static void main(String args[])
      {
          Scanner s=new Scanner(System.in);  
          String k=s.nextLine();
          NewClass12 ob=new NewClass12();
           if(k.length()==13)
           {
               k=ob.secure(k);
           }
           ob.print(k);
      }
}