Consider the following sequence

$$mathcal{S}=langle3,1,4,1,5,9,2,6,5,3,8,9,7,9,3,2,3,8,4,6,2,7,9rangle$$ We can imagine

some adjacent elements of $mathcal{S}$ as a number. For example,

$5$, and 3 and $8$ form the number $538$. We say two number in above

format is disjoint, if there is nothing common element between them.

With respect to $mathcal{S}$, what is the maximum number of disjoint

numbers we can make such that have increasing order from left to right?

I think if we consider only numbers with $1$ digit, then we have at most nine numbers that have no common element and sorted in increasing order from left to right. But the answer is $10$ numbers. Maybe i have a misunderstanding about the problem, so any one have a idea to clarify me that why answer become $10$?