Problem Statement

Takahashi will answer $N$ quiz questions. Initially, he has $X$ points. Each time he answers a question, he gains $1$ point if his answer is correct and loses $1$ point if it is incorrect. However, there is an exception: when he has $0$ points, he loses nothing for answering a question incorrectly.

You will be given a string $S$ representing whether Takahashi's answers are correct. If the $i$-th character of $S$ from the left is o, it means his answer for the $i$-th question is correct; if that character is x, it means his answer for the $i$-th question is incorrect. How many points will he have in the end?

Constraints

• $1 \le N \le 2 \times 10^5$
• $0 \le X \le 2 \times 10^5$
• $S$ is a string of length $N$ consisting of o and x.

Input

Input is given from Standard Input in the following format:

N X
S

Output

Print the number of points Takahashi will have in the end.