Hey Anil,

Try this:

CombineLatestStream(
  [
    email,
    password,
    address,
    //next 12 streams
  ],
  (values) => values.last
)
.listen(print); //prints 'C', 'D'

Check this link for detail: https://pub.dartlang.org/documentation/rxdart/latest/rx/CombineLatestStream-class.html