String str1=Long.toString(i);
long sq=i*i;
String str2=Long.toString(sq);
String l=str2.substring(0,str2.length()-str1.length()-1);
String r=str2.substring(str2.length()- str1.length(),str2.length());

java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Long.parseLong(Long.java:601)
    at java.lang.Long.valueOf(Long.java:803)
    at Solution.kaprekarNumbers(Solution.java:28)
    at Solution.main(Solution.java:49)