CF1159A.A pile of stones

Vasya has a pile, that consists of some number of stones. $n$ times he either took one stone from the pile or added one stone to the pile. The pile was non-empty before each operation of taking one stone from the pile.

You are given $n$ operations which Vasya has made. Find the minimal possible number of stones that can be in the pile after making these operations.

The first line contains one positive integer $n$ — the number of operations, that have been made by Vasya ( $1 \leq n \leq 100$ ).

The next line contains the string $s$ , consisting of $n$ symbols, equal to "-" (without quotes) or "+" (without quotes). If Vasya took the stone on $i$ -th operation, $s_i$ is equal to "-" (without quotes), if added, $s_i$ is equal to "+" (without quotes).

Print one integer — the minimal possible number of stones that can be in the pile after these $n$ operations.

In the first test, if Vasya had $3$ stones in the pile at the beginning, after making operations the number of stones will be equal to $0$ . It is impossible to have less number of piles, so the answer is $0$ . Please notice, that the number of stones at the beginning can't be less, than $3$ , because in this case, Vasya won't be able to take a stone on some operation (the pile will be empty).

In the second test, if Vasya had $0$ stones in the pile at the beginning, after making operations the number of stones will be equal to $4$ . It is impossible to have less number of piles because after making $4$ operations the number of stones in the pile increases on $4$ stones. So, the answer is $4$ .

In the third test, if Vasya had $1$ stone in the pile at the beginning, after making operations the number of stones will be equal to $1$ . It can be proved, that it is impossible to have less number of stones after making the operations.

In the fourth test, if Vasya had $0$ stones in the pile at the beginning, after making operations the number of stones will be equal to $3$ .