Declare Stream class that can hold numbers.
it has operations add() read() and remove()
you have to add or read or remove given number of elements to Stream.

Multi Stream (There are infinite number of streams)
add or remove stream to multi stream.
declare only one operation read.
read from multi stream, when you are done reading the first stream, the pointer has to set automatically to next stream and so on, when you finished reading all chars say null