Description

Given positive integers $N, K$ and an $N$-digit number, find the maximum value of the number remaining after deleting $K$ digits from the $N$-digit number.

Input Format

The first line contains two integers $N, K$.

The second line contains an $N$-digit integer. It is guaranteed to have no leading $0$.

Output Format

Output the maximum value of the remaining number.

4 2
1924

94

7 3
1231234

3234

10 4
4177252841

775841

Hint

【Constraints】

• For $50\%$ of the testdata, $N \le 1000$.
• For $100\%$ of the testdata, $1 \le K \lt N \le 5 \times 10^5$.

【Hints and Notes】

This problem is translated from COCI 2011-2012 CONTEST #4 Task 3 KEKS.

The score setting of this problem follows the original COCI problem, with a full score of $100$.

Translated by ChatGPT 5